SPE Papers 1920x1080
SPE Papers 1920x1080

Technical papers


Material and Equipment Testing Methodology in Simulated CO2 Storage and Transportation Environments Using Test Flow Loop facility

The rapid emergence of the Carbon Capture and Storage (CCS) industry as a relevant measure to mitigate global climate change, has resulted in a growing number of carbon storage projects. 

The captured CO2 is going to be safely transported and permanently stored underground in the geological reservoirs. To ensure safe and sealed storage of the injected CO2, the integrity of the injector wells will need to be assured. This can be done through a thorough understanding of the downhole or transportation environment during operational/transporting activities, as well as the impact of CO2 state and content.

The objective of this work is to describe different testing methods using a Test Flow Loop facility and the approach towards simulating, e.g., CO2 injector well environment in critical operational scenarios such as a shut-in period where formation water flow back may occur or a scenario of possible check valve failure where small amounts of formation water may enter and settle on the surface of the completion string causing severe corrosion.

Find the full paper at https://www.onepetro.org/


Metal Expandable Packer Isolating Shallow Water Aquifers on a Middle East Appraisal Well

During the planning phase of an offshore exploration well, Eni Abu Dhabi BV (Eni) had recognized the challenge of isolating shallow water aquifers across a 16″ drilled hole section, using a single stage 13-3/8″ cement sequence.

Through a multi-team approach, a combination of first-stage cement, a Metal Expandable Packer (MEP) and a contingency second stage-cement operation was identified as a solution to positively seal the C annulus and prevent Sustained Casing Pressure (SCP).

This was the first deployment of the MEP within the C annulus in the Middle East region. The combination of cement and MEP technology to address and eliminate the risk of SCP has many applications through the region, reducing risk, cost, rig time, and methane emissions.

Find the full paper at https://www.onepetro.org/


Restoring Production Via Non-Rig Deployed Wireline Technology

This paper details the challenges faced and the solutions deployed to restore production following failure of a formation isolation valve (FIV).

After the removal of the wellbore debris using a slickline bailer and a suction tool deployed with electric line (EL), a tractor milling assembly was deployed that successfully milled through the FIV ball-valve. The successful milling operation saved approximately $30MM in Major Rig Work Over cost by bringing the well back to production levels in accordance with the pre-drill estimates.

This paper describes the process followed to design an optimal intervention plan, and the detailed planning and operational steps. The optimal engineered solution coupled with operational discipline during execution successfully brought the well back to production, minimizing the lost production cost while avoiding a costly rig-based intervention.

This paper also highlights the novel technologies utilized, the milling BHA configuration, specific lessons learned, and best practices recorded during the execution.

Find the full paper at https://www.onepetro.org/


Dynamic E-Line Conveyed Milling Solution Remediates Subsea (XT) Gate Valve Operating From RLWI

An oil-producing subsea well located offshore Congo was equipped with an inoperable subsea vertical xmas tree (XT), in specific the production master gate valve in the vertical bore stuck at 55% to 65% open following the measurement of the valve stub.

The operator issued a challenge to the oilfield services industry to present a solution to mill the partially
open gate valve via RLWI vessel. The supplier responded with a solution that could mill the gate valve in
a single run, including recovery of the milled coupon. In addition, the solution would ensure that all the
operational well barriers remained free from obstruction in the event of the milling toolstring becoming
stuck, with fishing contingencies also in place.

This paper discusses the challenges and solutions related to milling a partially open gate valve on a
closed oil-producing subsea well using an RLWI vessel offshore Congo. It covers the project scope, solution
design, planning, equipment preparation, job execution, and provides estimates of risk and cost reduction
to as well the added production level resulting from this operation.

Find the full paper at https://www.onepetro.org/


Well Construction on Wireline

A further evolution of wireline intervention technique has emerged allowing mechanical manipulation in horizontal wells using a combination of Wireline Stroker and field proven Wireline Tractor technology - best described as Well Construction on wireline in a highly deviated well.

This technology represents a cost-efficient method for setting and retrieving of specific downhole hardware (i.e. plugs and straddles) as a resource-efficient alternative to existing technologies.

This paper will present the following case history and the benefits of the operation, particularly in deviated wells, where tractor technology in combination with the Wireline Stroker exemplify the advantages of this technology.

Find the full paper at https://www.onepetro.org/


New Electronics Ensure Increased Operational Efficiency in Highly Deviated, High Temperature Gas Well

This paper describes a case story from Saudi Arabia where an extreme downhole environment required new developments in electric line intervention technology. This operation was the first time the new DC electronics package was used in the Middle East.

A major operator needed to test casing integrity and perform a perforation on a high pressure/high temperature well (310°F, 91° horizontal well). Standard wireline conveyance was not an option, pump down logging wasn’t available, and coiled tubing was too time consuming. New technology had to be considered. Multiple feasibility studies, including heat studies, were performed to verify that an e-line tractor equipped with newly developed DC electronics equipment would be able to execute the job under the extreme well conditions.

The job consisted of two runs; the first conveyed a cement bond log and a multi calliper imaging tool to 18,725 ft. while the second run conveyed a 3 3/8" gun to perforate the desired zone at 18,725 ft. The e-line tractor worked as planned despite the high temperatures and the 18,725 ft. extended reach section. 

Find the full paper at https://www.onepetro.org/


Adaptive Strategy in Execution of Crown Plug Retrieval at the First Deepwater Subsea Workover Campaign

A thorough planning and preparation is very critical to ensure a successful deep-water subsea workover
campaign particularly the first one in the country. 

This paper will present the planning, process, execution and lesson learned during the operations.

Wireline intervention has always been prepared for various activities in recent subsea workover campaign
including being the contingency of crown plug retrieval. The conventional way to retrieve crown plugs is
using slick line jarring. If this method is not successful due to certain causes and equipment limitation due
to water depth (ranging between 400 and 1500 meters), a hydraulic electric stroking tool will be run to
pull out the crown plugs. 

Find the full paper at https://www.onepetro.org/


New Technique to Plug and Abandon Intelligent Well Completions with Flat Packs

The scope of this abstract is to highlight the complexities that arise when attempting to plug and abandon
(P&A) smart well completions. Just about every well that has a smart completion design includes flat pack

As part of the complex P&A operation the upper completion of the well must be retrieved. To retrieve
the upper completion, the production tubing and the flat pack must be cut or severed completely. If the cut is
partial there is a high probability of losing complete sections of control line and associated debris in the well
bore. This debris can potentially negate the possibility of providing a clean and secure well abandonment,
not to mention the high cost of non-productive time (NPT) due to fishing operations to remove the debris.

Two System Integration Tests (SIT) were completed to prove the concept of cutting through pipe and a
flat pack within a single operation, one with a 5 ½″ 23ppf S13Cr 95ksi pipe inside of a 10 ¾″ casing and
the second was with a 6 5/8″ 28ppf S13Cr 95ksi inside 10 ¾″ casing. Prior to inserting the 5 ½″ pipe into
the casing, a flat pack was strapped to the external wall of the pipe.

Find the full paper at https://www.onepetro.org/


Enabling High Performance Multi-Lateral Wells: Current Technologies and Gaps

This paper presents the current state of the industry in multilateral wells (ML) and presents the key findings
from a broad literature review and two knowledge sharing workshops hosted by the University of Calgary
and the Clean Resource Innovation Network (CRIN) in late 2021 and early 2022.

The technology to deliver ML wells is mature and has been demonstrated across thousands of wellbores around the world. Evaluation, characterization, and control of flows in ML wells is also possible using available technology, however, it is expensive and may be cost prohibitive. Modelling and optimization of flows from lateral legs may be done using existing reservoir simulators.

What generally limits the more widespread adoption of ML wells is the perception of elevated risk from decision makers, lack of familiarity with ML technologies, and the perceived costs of ML junctions and associated equipment and operations. By highlighting the technologies and successes, this paper aims to heighten awareness of ML technologies and further widen the adoption and implementation of ML wells.

Find the full paper at https://www.onepetro.org/


Sand Fill Clean-Out on Wireline Enables Access to Additional Perforation Zones in Gas Well Producer

An Australian operator wanted to explore options for wireline conveyed sand bailing in one of their offshore
platform gas producing wells. The objective was to remove twenty-six meters of sand fill inside 9.625"
production casing, with an internal diameter of 8.681". Due to the landing nipple at the end of the tubing,
the minimum run-in-hole restriction of the production tubing string was 3.987".

To limit the number of clean out runs, the latest technology in e-line deployed suction tools with a 4.25"
OD was chosen, which provided increased recovery volume over its smaller cousins, plus real-time surface
control and monitoring. Because of the tool's overall diameter, the landing nipple also required milling to
allow access. Therefore, a specially designed 4.412" mill bit was manufactured and run on a milling tool –
a tool requiring tractor conveyance to provide weight-on-bit and counter the reactive torque.

As the well had low deviation, the subsequent clean-out toolstring was run standalone (without tractor).
One of the key factors governing the feasibility of conducting this operation on e-line was the overall
toolstring lengths, where the lubricator height was limited to approximately sixteen meters.

Find the full paper at https://www.onepetro.org/


Metal Expandable Packer Secures the Integrity of a Cemented Casing Shoe and Protects the Caprock from Potential High Injection Pressures 

The Edvard Grieg platform and Solveig subsea field developments have four horizontal wells with a novel cap rock protection technology in place for water injection service. The 9 5/8" casing shoe is positioned within the cap rock providing the primary well barrier.

The 9 5/8" shoe was landed and cemented at the bottom of the cap rock, the mud weight lightened and the 8 ½" hole was drilled to Total Depth (TD). A single trip liner was deployed consisting of a liner hanger, a 7" casing with MEP and with contingency swell packers, positioned at the top of the injection reservoir, and 6 5/8" and/or 5 ½" sand screens with annulus flow prevention.

This solution addressed the challenge, securing a more robust and long term well integrity situation at substantially reduced cost and risk. The operator is considering wireless pressure gauges above the MEP in future applications to consistently confirm the MEPs as working barriers against high injection pressures.

Find the full paper at https://www.onepetro.org/


Novel E-Line Method Restores Well Barrier by Re-Establishing Communication with Control Lines

An offshore producer well located in the North Sea was designed to include control lines connected to a communication nipple enabling the installation of a wireline retrievable subsurface safety valve (WRSSSV) in case the downhole safety valve (DHSV) failed. 

However, the DHSV had become stuck in an open position, and attempts to open the communication port had been unsuccessful. This caused the well to be lacking a critical barrier and meant a potentially costly workover re-completion was required. An alternative solution in the form of an e-line conveyed surface-controlled cutting tool was proposed as a means to establish communication with the control line.

This novel e-line solution not only prevented the need for a costly workover re-completion operation, but also provided a safer and more cost-effective operation, with a reduced C02 footprint. It was a successful first-time application; the well was secured, and production was restored.

Find the full paper at https://www.onepetro.org/


Sustained Annular Pressure Prevention in the Vaca Muerta Wells Optimizing Well Construction Through the Utilization of Metal Expandable Packers Technology

Drilling and completing oil and gas Wells into the unconventional Vaca Muerta Formation (Fm.) has proven to be a challenging task since the beginning of the development.The unique characteristics of the several formations oil operators must drill through in order to reach Vaca Muerta Fm along with the extended reach horizontal sections, make the complexity of the drilling operation to become a constant challenge for an optimized well architecture.

To add up the extensive and demanding completions program, currently being executed with an average of 60 frac stages per well with a work pressure up to 13500 psi, make the construction of wells to be an even more challenging task.

An effective and proven solution, that can be integrated into the well's completion program helping to achieve the prevention of SAP, is the Metal Expandable Packer (MEP) technology. This new technology can help mitigate SAP eliminating the need for complex remedial operations that usually increases the costs and operational risks.The following paper shows the process of technology selection, qualification, job planning, field deployment of MEP and results.

Find the full paper at https://www.onepetro.org/


Innovative Use of Wireline Tools Enables Successful Re-Entry on Subsea Wells

Re-entry of subsea wells can always hide unforeseen difficulties. Contingency mobilization of coiled tubing
(CT) usually gives a wide spread of solutions to overcome most of the possible events.However, when operating on a winterized semisubmersible rig in the remote fields of the Barents Sea, rigup of CT spread can be costly and complicated. Furthermore, lighter and easily deployable wireline powered mechanical tools have proven to be effective in tackling most of the possible challenges.

Furthermore, lighter and easily deployable wireline powered mechanical tools have proven to be effective in tackling most of the possible challenges. Possible tubing obstruction issues can be resolved via clean-out/suction, pumping, or milling methods. In this instance, all three were used with different tools to clear the obstruction from the tubing and to clean with precision inside an internal fishing profile of a well head barrier plug to allow for well access.

The tools used were already available on the market for different applications. In this case the tools were
used in an alternative way, using their features to solve issues beyond conventional expectations. The result
fosters confidence to plan future re-entry without the need for mobilizing a CT spread.

Find the full paper at https://onepetro.org/

GRC 2022 ID#129

High-Temperature Expandable Steel Technology for Cement Operation Optimization

Optimal efficiency of geothermal resources is achieved through the correct combination of heat, fluid, and geological fractures to obtain optimal well performance. These fractures can be associated with the intersection of faults or structures which often results in partial or more frequently severe complete losses.

Metal Expandable Packer (MEP) technology offers an alternative or a supplement to a cemented casing, delivering an all-metal-to-rock-sealing isolation barrier at the setting depth, providing superior sealing. The solution has proven capability in reducing both drilling time and cementing costs (when applicable) and avoiding remedial workovers.

This paper will describe the technology and its qualification process, supported by case stories of MEP deployment on geothermal wells, and detailed value proposition information illustrating the overall cost and risk benefits. 

Find the full paper at https://www.geothermal-library.org/

GRC ID#266

Multi-Zone Completion Systems for Geothermal Energy Production in Sedimentary Rocks 

Low-temperature and unconventional geothermal projects are baseload solutions for energy 
production and heating systems. A combination of high fluid production rates and hightemperature fluids is necessary for high electrical generation rates when pairing binary cycle 
power plants with geothermal wells. 

This paper presents two different lower completion configurations for multiple zonal isolations in unconventional reservoirs that allow rotationally, work down, and full-bore capabilities of the tools. An existing case study will be presented where the success of the completion deployment was achieved, and the effective zonal isolation was accomplished.

The MEP and WFV incorporate corrosion resistance allow and high resistance elastomeric seals 
for temperatures up to 200° C, enabling a true Enhanced Geothermal Systems (EGS) completion 
for maximum efficiency and energy output. 

Find the full paper at https://publications.mygeoenergynow.org


Injection Enhancement in a Deep-Water Gulf of Mexico Multi Zone Completion Enabled by Downhole Multi-Position Flow Valves

The Deep-Water (DW) Gulf of Mexico (GOM) fields have a complex mix of multi-layered reservoirs, with thicknesses and rock properties which can widely differ from layer to layer within the same reservoir. Injection of 25,000 bpd of water from a shallower aquifer B4 sand via a dump flood technique, benefited from a variable and controlled zonal distribution of the injection into two separate layers connected to the producer B6 Sands over life of well.

This paper presents the modelling performed to achieve optimal choke selection, specified distributions, job execution and results of utilizing multi-position flow valves as part of the 3 ½" completion with the objective of achieving the optimal injection rates in the upper and lower layers of the BB Sands.

This is the first deployment for the multi-position flow valve with variable chokes in the deep-water Gulf of Mexico well environment. The solution provided controlled injection with variable rates into the two upper and lower producer sands, this technique enables a cost-effective and reliable proven solution which can be applicable to any type of injector well, with the goal to increase the overall NPV of the field, through the increased recoverable using a predictable and safer method of downhole flow control.

Find the full paper at https://www.onepetro.org/

GRC ID#1034504

Design and Qualification of and All Metal Expandable Packer for Effective Annular Isoaltion in Enhanced Geothermal System

Enhanced Geothermal Systems (EGS) face many lower completions challenges due to the 
extreme bottom hole temperatures in excess of 300 °C. The economic viability of EGS wells has 
a strong dependence on the effective stimulation of the isolated intervals within the well. 

This paper presents the test equipment design, the qualification results, and the engineering 
process from the selection, validation, and testing of the all-metal seal designs, to the full-scale 
qualification of an all-metal well magma packer with multiple redundant all-metal sealing 
elements to a maximum differential treatment pressure of 6,000 psi and 330 °C.

The novel all-metal expandable packer (MEP) will enable the required effective annular isolation 
of the EGS well for maximum efficiency and energy production.

Find the full paper at https://publications.mygeoenergynow.org


Production and Well Access Restored After a Successful Subsurface Safety Valve Flowtube Milling on E-line, Preventing Major Rig Workover

An offshore production well was out of operation after unsuccessful inflow tests. A remedial work plan was
designed, but the execution resulted in severe damage to the top of the flowtube inside the Subsurface Safety
Valve (SSSV), which was bent over and preventing production. Wireline conveyed mechanical intervention
was performed with robotic tools to mill the obstruction and regain full bore access.

Downhole hardware milling is a common technology; however, a thorough process must be followed in
order to succeed. The following factors were among those to be considered: well configuration (completion
schematic and restrictions); the material of the flowtube (9CR-1MO Martensitic Steel); the risk of damaging
the surrounding area; the risk of rotating the whole assembly while milling; and the risk of getting stuck
with the e-line Bottom Hole Assembly (BHA). The milling intervention program was drafted taking into
consideration different scenarios including contingencies.

This paper describes the complex yet efficient operation where a robotic milling tool, conveyed by eline, was able to remove a critical downhole obstruction and restore production while preserving all safety features of the well, thus preventing a complex workover operation. The in-depth preparation, followed by a methodical execution, allowed oil production to be resumed in this well.

Find the full paper at https://www.onepetro.org/


Heavy Duty Robotic Fishing Allowed to Restore Injectivity in Critical Well – A Case Study

An offshore injection well was out of operation after unsuccessful wellhead maintenance operation, when a
slickline Bottom Hole Assembly (BHA) was stuck inside Subsurface Safety Valve (SSSV). Several fishing
attempts with variety of technologies were unsuccessful. Heavy Duty robotic fishing tools were used to
retrieve the fish (acid syringe and soak sleeve along with slickline assembly) from SSSV, restore injection,
and provide well integrity.

Analysis of unsuccessful fishing attempts suggested that the main reason for failures to achieve the goal
was inability to provide sufficient force in controlled manner (without jarring), while there were no issues
to latch the top of fish. Robotic fishing tool consisting of stroker tool with 100,000-lbf force available,
reinforced with precise force and piston position control, in tandem with heavy duty overshot was proposed
for operation. An onshore test, replicating the downhole scenario, was performed during the preparation
phase to prove the concept and evaluate the functionality of the tools.

Fishing operation proven itself complicated - after successful latch and applied overpull, the fish started
to move up for limited distance as long as stable upward force was applied. Series of strokes within same
run were not able to completely free the tool, so the fishing tool was disconnected from the fish and pulled
to surface to be replaced with fresh one.

Find the full paper at https://www.onepetro.org/


First Successful Mechanical Cutter Cut Tubing Under Compression Including Three Different Types of Control Lines

One of O&G operator in Indonesia is scheduled to have a re-entry and drilling campaign at their deepwater
field. The re-entry program objectives were to cut 5-1/2", 17#, 13Cr-L80 tubing and POOH existing upper
completion prior P&A operation. A conventional way of tubing cut is putting the tubing in tension to prevent cutting blades got pinched and increase the chance of successful cut.

However, the challenge for tubing cutting at this well was not only to cut the multiple control lines but also tubing hanger was not preferred to be unlatched prior tubing cut. The mechanical cutter should be able to cut under compression and also reach control lines with total OD of 6.916". Mechanical cutter with new design tiger claw blade was chosen due to its ability to cut the tubing under compression and also the blade arms could expand increases the cutting range to 7.2" guaranteeing continuation cutting beyond tubular OD through the multiple control lines.

With the newly designed cutting elements, enabling a safe and efficient cutting operation. This solution
eliminates the risks of unlatching the TH and put tubing in tension, the cost of rig time and ensuring no
interruption to the well program. Operational details, including job planning and lessons learned will be
discussed in the paper.

Find the full paper at https://www.onepetro.org/


Utilizing E-line Mechanical Services to Fish a Slickline Running Tool and Heavy-Duty Pulling Tool HDPT - A Case from Malaysia

A productive offshore/onshore oil well had to be closed because a slickline plug set/retrieval operation
failed, leaving tool-string and isolation plug being stuck at a depth downhole. In order to free the tool, a
heavy-duty fishing operation was carried out using an electric wireline self-anchoring hydraulic stroking

In this case study, an operator in Malaysia had used the production packer in Well G. Following the
successful landing of the tubing hanger, the RN plug was installed at the RN nipple to initiate the setting of
the production packer. However, the RL running tool became stuck in the plug body and remained so despite
multiple jarring attempts (~200). 

Based on a highly successful SIT, all the equipment was mobilized offshore. Since there were two fish in
the well, two hydraulic stroking tools with 33k lbs. and 60k lbs. capability were assigned. Utilizing the 33k
lbs. stroker, the delivery of three strokes down and one stroke up resulted in both fish to releasing completely,
and they were subsequently retrieved to the surface, leading to the well being put on production again.

Find the full paper at https://www.onepetro.org/


Revolutionary Electrical-Mechanical Punching Solution for Remediation of Declining Hydrocarbon Production

An operator on the Norwegian Continental Shelf was confronted with declining production of hydrocarbons, making a particular well no longer profitable. The typical solution for this issue is to sidetrack and recomplete, however, this method is both time-consuming and costly. 

The existing completion of the well included multiple sand screens, where production of hydrocarbons was achieved through a single narrow nozzle for each screen. It was believed that these nozzles were fully blocked by scale and/or sand, and a potential solution was to punch or perforate the basepipe. However, any accidental puncturing of the screens would open the door to the possibility of increased sand production and would eventually kill the well. The only acceptable tolerance for penetration depth was 1.75 mm (0.0689”)

This study presents an innovative and cost-effective solution that eliminated the need for a costly workover recompletion operation and, prevented the potential failure of the well. By implementing the electrical mechanical punching tool, the operator was able to remove blockages in the sand screens with precision and control, leading to a substantial increase in hydrocarbon production. This approach offers valuable insights and a viable alternative for addressing declining production in wells with similar completion configurations.

Find the full paper at https://www.onepetro.org/


Wireline Retrievable Safety Valve E-Line Milling

Long-term downhole restrictions could potentially create unfavorable impacts for operators: impeding or
preventing production and any further interventions. A well in offshore East Malaysia had encountered a
stuck Wireline Retrievable Safety Valve (WRSV) issue, with its lock-mandrel partially parted after several
unsuccessful fishing attempts. The attempts were finally aborted, leaving the stuck WRSV downhole
without a fishing neck for almost 25 years.

In July 2019, initial engagement was made to re-establish access to this well for perforation and
production. The solution was to use an Electric Line (EL) milling tool with a tractor and customized milling
bit. The aim was to unlock the lock mandrel, which was holding the safety valve in place, and minimize any
trace impact of milling on downhole accessories as ability to re-utilize the nipple profile for future safety
valve deployments was also targeted, hence maintaining the assembly in a functional state was crucial.

This paper describes the process of designing the operation, and the subsequent execution phase

Find the full paper at https://www.onepetro.org/


World's First Fishing Operation on Wireline, Where 100,000 Lbs of Pull Force Was Applied: A Case Story

A high producing offshore oil well was shut down after an unsuccessful slickline plug-retrieval operation,
which led to the slickline toolstring and isolation plug stuck at a shallow depth. Heavy duty fishing was
performed using electric wireline self-anchoring hydraulic stroking tool. While pulling, 100Klbs of force
was applied to free the slickline toolstring from the plug. This paper is written to share the experience gained
while planning, preparing, and executing this high-profile job.

Base function test was performed to determine if the high force from the electric wireline hydraulic
stroking tool would break the slickline toolstring or release it from the plug. For the test, the exact fish
components, including the plug, were set up in a horizontal tubing. A long overshot was designed to swallow
the jars in the slickline toolstring. It took five upward strokes, up to 100,000 lbs, to release the slickline
toolstring from the plug's fishing neck. The ring of the fishing neck sheared from isolation plug.

Following the base function test, equipment was mobilized offshore. The heavy duty overshot was
installed on the fish using Slickline. Electric wireline hydraulic stroking tool was then rigged up on electric
wireline, run-in-hole, and latched onto the overshot.

Find the full paper at https://www.onepetro.org/


E-line Milling of Isolation Valve Restores Well Access in the North Sea

Milling interventions can resolve a variety of issues related to downhole restrictions, and these extend
beyond remediation of typical scale buildup. One such problem or challenge is that of downhole hardware
becoming stuck or no longer functioning properly.

The e-line toolstring consisted of a tractor and a milling tool with a specialized milling bit. The function
of the tractor was twofold, providing conveyance to target depth as well as countering the torque of the
milling tool during the operation. A Power Suction Tool was also included as a contingency for potential
fishing of milled hardware/debris. During the run, after tagging the valve, hardware milling was carried out
in two three-hour stages. The valve was completely milled through, collected as two pieces (half-moons)
in a single run.

The operation resulted in the removal of the restriction and enabled access to the section of the well
below the isolation valve. With the operation requiring just 8.5 hours, the solution provided significant time
and cost savings to the operator.

Find the full paper at https://www.onepetro.org/


Metal Expandable Packers Deliver Cement Assurance for Improved Well Integrity

Operators globally are consistently challenged to deliver effective cement sealing for Zonal Isolation (ZI)
between reservoir units and to prevent Sustained Annulus Pressure (SAP). This paper discusses such a
challenge for a land well drilled in West Africa and how these challenges were addressed. The challenge
was to achieve effective ZI of a depleted sand gas reservoir and provide B annulus isolation to prevent future

The challenges arose from a combination of losses (during drilling and cementing) and potential gas
invasion into the cement during the cement curing process. The solution utilized three Metal Expandable
Packer(s) (MEP), two of which were expanded within wet cement. The MEP purpose is to deliver ZI
Cement Assurance (CA) across the reservoir and one MEP set above Top of Cement (TOC) within the
Open Hole (OH) to protect the B annulus from (SAP).

Both solutions improved the overall well integrity, providing mitigation from cross flow, early water production and the risk of methane emissions release into the atmosphere.

Find the full paper at https://www.onepetro.org/


Removing the Requirement for Deburr Runs on a Field Development Multizones Well Completion

A Metal Expandable Packer (MEP) as an Inner String Packer (ISP) that has the capability to run through
multiple perforated zones, without the need for a deburr run was qualified for a BSP oil & gas field
development in Brunei. Four injectors and four producers will be developed across a stacked sand shale
sequence, requiring zonal isolation (ZI) and flow control to maximize production. The inclusion of this
MEP technology provides a robust life-of-well Cased Hole (CH) sealing system with inherent anchoring
and removes the deburr run, reducing associated rig time and cost.

Initial design for Shell Whale proved the sealing capability of the MEP after passing through a nondeburred 9-5/8″ perforated liner. The BSP well design and qualification required an MEP to pass through
a 7″ cemented and perforated liner deployed on a 3-½" inner string comprising up to six zones – each
zone with a mechanical sliding sleeve and control line for zonal Permanent Dowhole Pressure-Temperature
Gauges (PDHG).

Further application of the MEP on multi-zone completions will enhance the ZI (sealing) of the 7″ to 8 ½"
rock face (cement assurance or cement replacement) and may ultimately lead to the multi zone completion
deployed within the open hole (OH) delivering further substantial cost reduction.

Find the full paper at https://www.onepetro.org/


E-line Deployed Robotics and Stimulation Workflow for Pilot Horizontal Well

This paper will outline the challenges faced and solutions employed to enable selective stimulation of a pilot
horizontal well in the Tengiz field by mechanical manipulation of fracturing sleeves utilizing an electric line
deployed tractor system. Specifically, how the robotic system enabled successful and selective stimulation
of nine acid fracturing stages in a challenging operational environment. The scope reviews the planning and
execution methodology utilized to enable selective stimulation and production along the lateral section.

While evaluating the concept of drilling a horizontal well through a deeper, previously undeveloped
reservoir horizon, it was identified that multiple acid fracturing stages would be required along a 1,000-
meter lateral section. The well objectives were such that each of the acid fracturing zones required the
ability to be selectively stimulated and produced (selective shut-off of zones post-production if required).
This design utilized an open hole completion with compartmentalization via swell packers and fracturing
sleeves. Due to the trajectory and horizontal nature of the well, electric line deployed robotics were selected
to access the fracturing sleeves.

The well was successfully drilled and completed in 2019 and stimulated in early 2021. All zones
were effectively accessed utilizing the selected intervention and stimulation methodology. This was the
first use of a robotics intervention technique in the Tengiz field. It was also the first horizontal well
drilled and completed into the target reservoir horizon. Intervention challenges included high pressure/high
temperature, H2S, well restrictions, drilling muds (with weighting agents), and of course the trajectory of
the well with ~ 1,000m lateral section to traverse. The successful outcome was a result of the conceptual
engineering, planning and execution of the intervention and stimulation work scope. 

Find the full paper at https://www.onepetro.org/


Successful Deployment of Metal Expandable Annular Sealing Systems in High Extended Reach Wells

The successful deployment of metal expandable annular sealing systems in extreme reach design wells completion. The design and engineering of this technology resulted in the development of a fit for purpose, state of the art equipment that overcame several challenges such as having the liner with full rotational capability to overcome the drag during the deployment while maintaining the full liner torque capabilities.

The metal expandable annular sealing system was designed to provide high expansion in potentially washed-out wellbores and across formations where effective isolation may not be achieved by primary cementation due to low formation gradient or cement design challenges in horizontal wells. The design included a long multi element sealing system with built in redundancy. The multi sealing element system chosen for this application due to it being a full bore, rugged, all welded, metallic construction with a constant, high ∆p over full expansion range. The system is fully rotatable during deployment, it also allows for high-rate circulation because of its slim OD.

The metal expandable annular sealing system was run in total or partial losses multiple times, and it was observed that circulation was gained after setting the metal expandable system. Furthermore, it was also confirmed that the system effectively provides zonal isolation by injecting into compartment and ensure that zone is completely isolated.

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Buzios Presalt Wells: Delivering Intelligent Completion In Ultra-Deepwater Carbonate Reservoirs.

This paper describes the challenges faced on the deployment of intelligent well completion (IWC) systems in some of the wells built in Buzios field, mostly related to heavy fluid losses that occurred during the well construction. It also presents the solutions used to overcome them.

The well engineering team developed a new well concept, where a separated lower completion system is installed in open hole, delivering temporary reservoir isolation. This new well architecture not only delivers reduced drilling and completion duration and costs, but also provides the IWC features in wells with major fluid losses.

Other important aspects considered on the new well design are the large thickness and high productivity of Buzios field reservoirs, as well as the need of some flexibility to deal with uncertainties. Finally, the new completion project was also designed to improve performance and safety on future challenging heavy workover interventions. The well construction area has gradually obtained improved performance in Buzios field with the adoption of the new practices and well design presented in this paper.

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Game Changing Cementless Annular Isolation Improving Economical Returns in Deep Water Wells

This paper will discuss a game-changing and innovative technology that enabled cementless annular isolation (liner to borehole) across the reservoir, removing the risk of previous experienced cost and time overrun from complex cement operations and securing the full economical return on the wells.

The technology has been deployed in four Moho North Albian wells, drilled through a complex reservoir with highly laminated lithology requiring efficient zonal isolation for both acid treatment and water shut off.

During the earlier field development, many cementing challenges were encountered that increased risk and cost and the ability to deliver effective isolation across the reservoir. Poor isolation leads to poor matrix acid stimulation, higher skin and a higher risk of water production. To address this the operator sponsored an industry challenge to achieve reservoir isolation with cost and risk reduction and to deliver overall efficiency gains. Through dialogue between the Operator and a leading service provider in Open Hole Zonal Isolation, a solution was identified that would effectively replace the cement across the reservoir with a metal expandable annular sealing system.

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Innovative Multiple-Zones Injector Completion Design in Unconsolidated Sand. A New Deployment Challenge in Highly Deviated Well in the Gulf of

The completion of a highly deviated well involves overcoming significant deployment challenges during the drilling operations that require precise and effective conveyance and intervention.

The conventional slickline intervention is unsuitable for wells with more than 60° deviation. The operator has sought to implement efficient, reliable and cost-effective deployment methods in delivering injector well. Thus, the operator decided on the e-line tubing tractor conveyed with e-line key and an e-line stroking tool.

A tubing tractor and mechanical key and stroker were used to convey the wireline key in highly deviated wells. The key and stroker tools are latched into the sliding side doors (SSDs). They will activate open or close SSDs by down-strokes or up-strokes. In particular, the SSDs are closed when it is required to pressure up the tubing to set the packers. After the packers are set, an integrity test is conducted to confirm zonal isolation. Finally, the SSD is shifted open by the tubing tractor and a low rate injection test is performed to confirm the status of the SSD before handover the well.

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The Case for Combining Well Intervention Solutions to Optimize Production and Reduce Risk Exposure.

While optimizing hydrocarbon production, combining well intervention solutions can enable significant benefits due to reductions in risk exposure: fewer rig-ups and downs, less in-the-hole operating time and the carbon production and costs associated with rig time, especially when working from sub-sea intervention vessels.

Operators in general, prefer to achieve multiple intervention objectives in a single descent in the well, if the operations complexity does not increase the risk exposure to an unacceptable level. Often, the risk of a mis-run, causing a second run, meets the cost vs value criteria for acceptable risk, when the large
operating time savings of a successful combined run is considered.

In collaboration with a mechanical e-line provider, North Sea operators developed three reliable combination solutions which increased their operational efficiency. Combining these most run services under more standard, common scope of work procedures, saved the operator time in planning, execution,
risk exposure and money, while enabling them to produce hydrocarbons in the saved time. This paper will present the technology involved with these combined services, use a typical example of each and the cost savings achieved.

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Cementless Well Construction Opens the Full Control on Well Integrity for the Life of the Well

Well construction has relied on two main elements, casing and cement, to achieve the well goals while
maintaining the highest possible well integrity. Can cementless well construction achieve similar goals?
This paper is investigating the various well construction concepts proposed over the years and will analyze
the cement's ability to withstand long term well loads.

First, a review of various well construction concepts such as slimhole, conventional, pre-salt and
horizontal wells. We will normalize the casing to cement thickness ratio by validating and proposing a
simple mathematical calculation for establishing this ratio. Our calculations have shown that in the case of
slimhole well concept, the thin cement sheath cannot serve as a strong well barrier as defined by current
standards, and thus a new solution might be necessary.

The second part will look at current new trends in wellbore construction that include external casing
packers and other solutions such as metallic wellbore isolation solutions.

The paper will conclude with one possible solution that could be used to mitigate cement problems
by shifting the well construction concept to a cementless new era. Also, understanding that the cement
manufacturing process is highly CO2 intensive, emissions per well could be reduced through the newly
proposed concept.

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Well Cutting Without Explosives with Multiple Cuts on a Single Run.

Pipe cutting operations are often a critical part of stuck pipe situations, well interventions and plug and abandon operations which all need to remove cut sections of pipe from the well.

Unlike traditional ‘blade’ style e-line cutters, which can jam under pipe compression or explosive pipe cutters, which need to dressover the jagged cut by the rig, a new electric line mechanical cutter's unique design enables performance even if the pipe is under compression, in tension or is neutral. It can also perform multiple cuts in the same run, while creating a clean and machined cut with tool-entry friendly shape.

This paper will describe the technology of the new generation cutter, present two case histories; one of multiple cuts of stuck drill pipe, per each run in hole, from Germany and one of a critical tubing cut from a subsea well in Nigeria, using electric wireline and tractor conveyed services for many tasks traditionally performed with coiled tubing in highly deviated wells. These "light vs heavy" solutions can often be done off-line from the rig.

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Securing Zonal Isolation Across a Highly Depleted GoM Deep Water Reservoir

Effective zonal isolation within a layered reservoir in the Gulf of Mexico is a necessity to meet regulations for stacked reservoirs and to maximize total recoverables. Effective zonal isolation also ensures maximum production is achieved via a high-pressure proppant fracture treatment.

A primary cement operation of a 10 1/8" production liner (within a 12 ¼" drilled hole section) was challenging due to a combination of high equivalent circulation density (ECD) and potential losses across a layered GOM reservoir. One layer had potential and significant depletion up to 8,000 psi. Critical well parameter considerations were: maintaining the liner burst of 18,200 psi, maximizing rotation and reciprocation capability of the liner, minimizing the impact on circulation and ECD, and ensuring compatibility with the mud systems.

Following careful job planning, including the analysis of caliper data from logging while drilling (LWD) for the optimum placement, two metal expandable packers (MEPs) were installed on the 10 1/8" liner. The MEPs were positioned to straddle the highly depleted layer (one above and one below) in the 12 ¼" open hole section. The liner was deployed, and the cement operation was executed with minimal ECD impact from the inclusion of the MEPs. Surface pressure was applied to create sufficient differential pressure across the 10 1/8" liner wall to hydraulically expand the MEPs quickly under full surface control.

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Construction of a Multipurpose Exploration Well in the Jurassic Deposits Subsequent Transfer to Production Enabled by Metal Expandable Barrier Installed Behind the Casing

The resource base of the north of the West Siberian oil and gas province is the basis of Russia's energy strategy. Among the northern territories of the province, the Nadym-Purskaya, Pur-Tazovskaya and Yamal oil and gas regions (OGRs) are the leaders in terms of estimated gas reserves. However, the largest deposits of the first two OGRs are in the stage of falling production.

Therefore, the main prospects should be associated with the Yamal OGR, which has not yet been put into active operation. It is logical that along with the development of traditional methods of extraction of "dry" natural gas, the government of the Russian Federation has approved a plan for the production of liquefied natural gas based on the fields of the Yamal Peninsula, which is currently being actively implemented by PJSC "NOVATEK".

At the same time, the degree of exploration of the resource base of the Yamal OGR (the ratio of reserves of category C1 to reserves of category C2 and resources D0 + D1) is relatively high - 0.48. This suggests that the potential for reserves growth is very limited. To further maintain production, it is necessary to introduce promising oil and gas resources into prospecting-exploration drilling right now.

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Minimization of Greenhouse Emissions in Russia and Kazakhstan Upstream Sector Through Optimized Well Construction Designs and Lightweight Mechanical E-Line Operations

The transition to a climate-neutral society is both an urgent technical challenge and yet long-term CAPEX heavy requiring huge investments from industry and governments. Major oil and gas (O&G) operators around the globe have already established their decarbonization targets and even though upstream accounts for two-thirds of total emissions in the petroleum industry, both new well construction designs, and improved workover operations are proving to be effective measures in minimizing greenhouse gas (GHG) emissions while being economically viable.

A novel completion technology has been installed in 114 wells in Russia since 2018 to eliminate sustained annular casing pressure (SAP) throughout the lives of wells and combat the associated release of carbon dioxide (CO2) and methane into the atmosphere. Since methane is much more powerful and has a 28-34 times more global warming potential compared to CO2 over the hundreds of years, and 84-86 times more potent over a 20-year timeframe respectively, these types of simple, yet efficient solutions represents enormous benefits to operators in reducing their carbon taxes while tackling climate change.

Moreover, the installation of this technology resulted in reliable downhole well integrity of traditionally problematic wells, without the need for subsequent squeeze cementing operations. These types of completion solutions set both in an open and cased hole, allow operators not just to customize their cementing program and meet regulatory approvals, but also greatly reduce their reported carbon emissions. A summary of the results and efficiencies achieved with these installations will be presented and will be compared to conventional technologies.

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Successful Deployment of Metal Expandable Technology with Inner String Stage Cementing System Overcomes Well Construction Challenges in Bab Field, UAE

Inability to effectively isolate depleted aquifer formations due to severe losses during cementation leads to accelerated corrosion of the production casing. Per current practice, a top job is performed from surface to fill the annulus with cement, but with limited success in a severe losses’ scenario.

The objective is to improve zonal isolation by applying V0 rated multiple stage cementation technology with inner string thus enhancing well integrity during the life cycle of the well.

A metal expandable annular sealing system was selected as a reliable isolation mechanism for effective cementation behind aquifers due to its ability to provide high expansion in potentially washed-out wellbores and the feature of long multi-element sealing systems with built in redundancy.

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SPE- 206626-MS

Applying of robotic equipment to perform production logging operations in extended horizontal exploration wells equipped with the Y-Tool system

This article describes the implementation process for use of robotic equipment to perform production logging in extended horizontal production wells equipped with a Y-Tool bypass system.

The article describes in detail the process of searching for technological solutions from bench tests to the introduction of technology in the field.

The described technology allowed the Company to find a solution to work with the Y-Tool bypass system in the production wells of the Prirazlomnoye field.

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A Case of Achieving Sustainable Annular Sealing in a Deepwater Marginal Nigerian Field

The industry has been relying on cement as primary method for annular sealing. The initial evaluation considers a formation integrity test and a cement bond log. This shows good results in 85% of the cases and cement squeeze is the main remediation method. The ultimate measure of the sealing performance is production: more than 50% of the wells have sustained casing pressure in the B-annulus or are producing in degraded mode. Additional solutions are required to improve the sustainability of the industry.

The present paper discusses a case history in a marginal well in Nigerian deepwater. Primary cement evaluation was successful, in line with the industry statistic of 85% successful cases. However, production started with 60% Basic Sediments and Water (BS&W) and after six months of production, the well was shut-in due to excessive gas production. The investigation identified that the target Turonian oil sand was separated by thin shales from bottom water and gas cap.

In the sidetrack, two Well Annular Barrier (WAB) were used to augment the cement. The WAB is a metalexpandable packer that sets in open hole to assure sealing. One WAB was installed between the oil zone and the gas cap, and another one between the oil zone and the bottom water. The operation was successfully executed and the WABs expanded in wet cement after bumping the plug. Three years later, the well is still producing with 0.2% BS&W.

This paper discusses the well conditions that contributed to insufficient cement sealing, the WAB
application in the field, and the field results.

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Disruptive Surgical-type Gate Valve Milling with High Precision Technology in the Gulf of Guinea

This paper presents a groundbreaking well intervention approach that comprehensively validates the need for operators to adopt game-changing technologies with razor-sharp precision during downhole milling on electric wireline. In early 2020, for the first time globally, electric wireline milling technology was utilized to successfully mill through a failed 2.25” gate valve.    

In this case study, the Upper Master Valve of well-X in an offshore location (Gulf of Guinea) was confirmed stuck in a closed position for over a decade. After several unsuccessful manipulation attempts were made by the client to gain access to the well, an electric wireline valve milling approach was considered.

This approach can be said to have established a springboard upon which future well intervention operations can be developed, mainly for milling through mechanical restrictions, as this was the first ever 2.25” gate valve milling operation performed on electric wireline worldwide.

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Unique Openhole Metal Expandable Annular Sealing Systems In High Pressure Multistage Fracturing Completion

This paper describes a game-changing solution regarding the use of metal expandable annular sealing systems in a high pressure multistage frac well. The design and engineering of this technology resulted in the development of fit-for-purpose equipment that overcame challenges often encountered in a highpressure stimulation environment.

The metal expandable annular sealing system was custom designed in order to provide high expansion that can be set in potentially washed out wellbores. The design included a long multi-element sealing system with built-in redundancy to account for fracturing fluid chemical reaction with the rock behind the seals

The system is just under 4 meters, complemented with multi-elastomer seals, each delivering full Delta P capability within a washed-out hole up to 6.5”. The unique design allows full rotational capabilities during deployment, minimizing operational risks.

The system was run in combination with multi open-close fracturing sleeves and a pressure activated toe sub rated to 10,000 psi for acid fracturing in three zones of a vertical carbonate well – the well was known for its heterogeneity and high reservoir pressure contrast. The use of mechanical packers with short sealing elements would have been challenging and increases the risk of unwanted communication between zones. Successful installations, activation of the sleeves and subsequent hydraulic fracturing were achieved, which enabled operational flexibility, reliable isolation and high expansion benefits. Acid fracturing treatment data from each of the stages were analyzed and used to confirm that the zonal isolation integrity.

This paper includes the challenges of providing zonal isolation with conventional packer designs and details the design, testing and qualification of the solution as well as further design modifications for higher fracturing pressure rating.

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Wireline Conveyed Robotic Intervention for Obstruction Cleaning and Sampling in Horizontal Wells Completed with Open Hole – Worldwide First Job Experience.

The objective of this paper is to share the experience of first worldwide job where wireline conveyed robotic cleaning tool was utilized to clean the obstruction in open hole section of oil well while collecting of uncontaminated sample of blockage material.

Wireline conveyed, lightweight, robotic intervention tools were used in one of fields in Saudi Arabia to collect uncontaminated sample of obstructive material for future chemical treatment and to remove the bridge in Open Hole section of oil well, so Workover Rig or Coiled Tubing intervention can be avoided or significantly deferred. Operation was performed without killing the well and with no additional fluids pumped into well, reducing possible intrusion and skin build up. This technology was run first time in world practice to clear an obstruction in Open hole section.

Severe planning was performed prior to technology introduction, including possible solutions comparisons and risk assessment. Robotic intervention was proven not only technically superior, but yielded large economic benefits compared to traditional descaling and sampling methods. It involved less personnel and produced much less CO2 footprint as well.

Sample retrieved during the operation was analysed in laboratory and with high degree of certainty can be attributed as localized formation collapse. Same was confirmed by limited length of blockage that was successfully removed. This represented additional mechanism of wellbore restriction in the field.

The experience from first worldwide operation, the methods and tools descriptions, process, lessons learned, recommendations and way forward will be presented in this work and should be of great interest for wide group of practicing engineers.

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A Comparative Review of Production Logging Techniques in Open Hole Extended Reach Wells

Successful reservoir surveillance is a key component to effectively manage any field production strategy. For open hole extended reach horizontal wells, including some wells over 30,000 ft in length, the challenges to successfully deploy real-time logging tools are greatly magnified. This is further complicated by constraints in the completion where Electrical Submersible Pumps (ESP's) are installed. A comparative review of the latest technologies and methods available to overcome these challenges will be explored.

The challenges are formidable and extensive; logging these extreme lengths in cased hole would be difficult enough, but are considerably exaggerated in the open-hole condition. The logging run in open hole must also contend with increased frictional forces, high dogleg severity, washouts and an increased well bore rugosity. The main challenges to achieve the logging objectives in open hole extended reach wells, are 2-fold, namely;

  1. To log the entire open hole section and reach the Total Depth (TD) of the well.

  2. To obtain high quality data from the logging tools, despite the adverse downhole environment.

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Full-Scale Validation Test of Liquid Assisted Gas Lift LAGL

A new and transformational gas lift method termed Liquid Assisted Gas Lift (LAGL) has been developed. LAGL utilizes the co-injection of liquid with lift gas to reduce surface pressure requirements for the kick-off of gas lift, simplify well completions and improve system reliability/flexibility. PetroleumETC executed a Shell GameChanger project to demonstrate the delivery of LAGL for well unloading and kick-off of gas lift. 

Qualification testing was performed at a university test facility utilizing a 2,788 ft TVD test well with 5 ½-inch casing and 2 7/8-inch tubing. Air and water were the test media. In-well measurements were available bottomhole and mid-string for both the annulus and the tubing. 

The test well was successfully unloaded in 2 hours with a maximum pressure of 535 psig using manual operation of the module. Two automated tests were successfully conducted; one requiring 2 hours (670 psig max pressure) and one requiring 1 hr and 24 min (724 max pressure). 

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Cost Effective Long Interval Wellbore Cleanout Using Wireline Technology: Field Application in Peciko Field, East Kalimantan

Mahakam field was experiencing gas production decline in some offshore wells. Previous interventions done in the past indicated the high probability of scale and sand which had reduced the production flow path, it had also prevented perforation gun from reaching the target depth in order to perform additional perforation to increase well potential.

Considering existing perforated reservoirs in the wells were still productive, Pertamina Hulu Mahakam (PHM) preferred to use well clean out method without invading/damaging open reservoirs. The additional cost of lost or deferred production was always unwanted.

The deployment of traditional rig or coiled tubing unit to help restoring production came with considerable cost due to the equipment and personnel requirements. Consequently, PHM continually looked for new techniques to reduce this challenge. Milling on wireline, where applicable, was one solution since it could be performed in rig-less environment.

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Long Lateral Restriction Diagnosed by Camera-Caliper Combo on E-Line Tractor in One Run

An operator in west Texas experienced an obstruction pumping down a plug and perforating gun combination on a multi-stage frac operation in a 23,600-ft lateral. Following a 3.74" OD gauge run with 2-3/8" coiled tubing (CT), which hung up at 18,266 ft, a 3" gauge run was able to pass the holdup depth (HUD). To determine the cause of the restriction, the operator decided to run a video camera and a multi-finger caliper tool.

However, due to some concerns with CT reach in the long lateral, issues with friction reducers, undesirable memory timers for recording the logs, and the inability to repeat logging in zones of interest or missing data, the camera provider recommended the logging be performed in "real time" on an electric-line (e-line) tractor.

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Worldwide First Successful Production Logging of Tri-Lateral High Temperature Coiled Tubing Drilled Sour Gas Well, Performed in a Single Run Using Innovative Reentrance System Without Whipstock Guides.

The job results from an operation using a wireline-operated lateral access tool (LAT) with a production logging tool (PLT) on E-coil are presented. The objective was to successfully identify, enter and acquire production data in each of the openhole laterals as well as the main borehole in order to quantify production and identify any cross-flow.

This operation is enabled by the use of a wireline-operated LAT. The tool can identify where the lateral window is located in the well and provide orientation data. With the LAT, the bottom sub can be indexed to enable entry into the lateral, while sensors package would provide positive confirmation and identification of a particular, targeted lateral. 

The system is compatible with a number of mono-cable logging tools and can be deployed using both E-line as well as Coiled Tubing. This paper describes the operation in detail and discusses the output and evaluates the results, which demonstrate the efficiency and accuracy of finding and entering the laterals.

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Successful Retrieval of Stuck Profile Plug Using Electric-Line Deployed Robotic Well Intervention Techniques

The subject well is a recently drilled and completed in Cambay field offshore in West coast of India. After landing the completion, two mechanical plugs were installed to nipple down BOP and nipple up X-mas tree. The plugs were installed in a 3.875" tubing hanger profile and in a 3.813" SC-TRSSSV selective profile. The problem arose while retrieving the 3.813" selective plug with 4" GS tool after installation of X-mas tree. 

he slickline wire snapped while doing the jarring operations resulting in fish in the well with BHA and plug slipping down below the selective profile. The plug fell inside the well and got stuck at the 4.5" × 3.5" tubing crossover joint ~20m below the SC-TRSSSV depth.

The fished slickline wire along with the slickline tool-string BHA was successfully retrieved from the well, however, the plug remained stuck at the 4.5" × 3.5" tubing cross-over and could not be fished out even after several conventional approaches with slickline.

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Electrohydraulic Tractor and Associated Mechanical Technology Platform Developments Deliver Precise, Controlled and Highly Effective Capability for Efficient Completion Component Milling

This paper discusses new electronic and hydraulic developments applied to the tractor-milling platform.
Case histories will demonstrate the hi-fidelity measurement, independent control and optimisation of all
relevant milling parameters adjusted on the fly, delivering performance across all stages of the milling

They will show the high level of instrumentation now available which ensures the milling
operation is conducted within prescribed and tested limits and allow performance parameters, designed
and demonstrated in the lab, to be replicated one-to-one in the downhole environment. Improvements also
include specific bit designs that have been developed though a rigorous testing program to minimise tool jamming and the metal debris created during the milling process, which could inadvertently cause other
issues in the well.

The technology enables switching between the tractors driven and rolling rotational anchor functionality
whilst providing continual rotation and back-reaming capability to minimise the possibility of a stuck
tool scenario. The case histories show that these developments have delivered unprecedented success in
challenging cased hole milling operations.

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World's First EGF Flapper Milling Via E-Line

Diagnosing and resolving unknown well obstructions at high deviations presents significant challenges to Operators. Combining a downhole camera with an electric line (e-line) tractor enables operators to traverse high angles and view the camera feed in real time, options unavailable on conventional Coiled Tubing (CT) unless running expensive smart CT. 

Furthermore, with e-line already on site, the operator maintains the flexibility to rig up an e-line milling tool to mill the obstruction. This paper describes how e-line tools helped identify the obstruction in a shut-in well and successfully milled the EGF ceramic flapper for the first time.

Earlier this year, in a gas field offshore East Malaysia, an Operator needed to investigate probable sand intrusion from an open-hole gravel pack prior to design a remedial plan to reactivate the well.

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Precision Surgery for Well Workover: An Innovation in Well Intervention

Conventional well interventions using drill pipes, coiled tubing, and slickline suffer much from inaccuracy, absence of downhole control, and lack of surface monitoring. The oil and gas industry has been pushing for a better, lighter, and more innovative approach. 

During the last 25 years, emerging downhole electric and electrohydraulic tools deployed on electric line (e-line) have gradually replaced some conventional methods, enabling more efficient and precise operational execution with the help of surface read-out data and real-time monitoring while controlling the downhole tools via commands sent through the e-line, adjusting to the needs transmitted by sensors integrated in the tools themselves. 

The results have been well received, and precision has become a necessity in certain well interventions, especially where the life of a well is expected to extend and the recovery to become more sustainable. Consequently, precision interventions save considerable time and cost to the operators while offering safer alternatives to other methods.

In this case, we show how two cutting-edge, e-line technologies have solved two important challenges for an operator: (1) Orienting an e-line puncher tool sideways to secure circulation when punching tubing at high deviation, and (2) cutting tubing in compression without damaging the outer casing, leaving a clean, beveled edge for subsequent runs.

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SCSSV Flapper Milling Using E Line Solution

This paper discusses the success of an operation involving E-line unit to mill Surface Controlled Subsurface Safety Valve (SCSSV) flapper on a well, which has been detached from its hinge. The flapper has become obstruction to well intervention activity on this well, preventing a zone shifting job which potentially would triple the well's oil production.

The SCSSV flapper becoming a restriction was identified from slickline tubing clearance job, but the fact that it has been detached from its hinge was learned after getting the result from running downhole camera. The objective of the operation is regaining access to the zone below SCSSV for zonal isolation and perforation.

The bit was specially designed to mill the flapper while minimizing the flapper rotational action that might have caused by the milling, hence increasing the milling effectiveness. As this is the first loose SCSSV flapper milling for Medco E&P Natuna, a System Integrity Test (SIT) was conducted at Service Company facility with actual flapper of the same type to prove the method would work, prior to the actual job onsite.

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Multilateral Reentry System for Well Surveillance: Design, Implementation and Summary of 40 Jobs Performed in Fields

Multilateral wells are a popular choice for fields where maximum fixed asset utilization is required. Although Drilling and Intervention (Stimulation) techniques for such wells are mature and reliable, reservoir surveillance required novel method for lateral access. Such technology was developed and used in more than 40 wells in Middle East. Summary of experience, description of tools and methods, lessons learned and vision for further development will be described in this work.

In order to be useful for lateral reentry and logging, intervention system should comply with following minimum requirements:

  • Be compatible with logging tools and systems provided by various Service companies and with various conveyance methods.

  • Operate with logging systems, not equipped with wired through capability.

  • Be of slim design so it can be used in variety of completions.

  • Be equipped with diagnostics systems to detect laterals and confirm successful entry.

All these requirements were implemented in new Multilateral reentry system. Once in field, system was proven reliable and useful for logging intervention in multilateral wells in various operating conditions.

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Significant Time Reduction and Cost Savings Realized Through the Use of Wireline Deployed Milling Services, to Enlarge a Tubing Hanger

A producing well located offshore Congo was equipped with a TRSCSSV which failed to open. A velocity valve, with a stem beneath, had been installed to keep the flapper open. This condition, apart from restricting the production, was a temporary solution as defined in Eni's (the operator) well integrity policy; for this reason, the SSV had to be replaced. In order to do so, the completion needed to be removed, which implied cutting the cut-to-release packer. 

A lock open tool needed to be run in the SSV to allow the cutter to reach the packer. The lock open tool was too big to pass the tubing hanger. Eni issued a challenge to the service industry, to come up with a solution to enlarge the hardened tubing hanger while preserving its mechanical integrity. The solution also had to be deployable quickly as the drilling unit could incur costly standby.

The retained solution used a wireline deployed milling toolstring equipped with a diamond coated bit. The benefits of this solution impacted several areas: the surface read out system allowed for fine control of the milling operation, the combinability of the tools allowed for adequate planning of potential fish recovery while retaining well barriers on a live well and the size of the equipment allowed for a rapid overseas mobilization.

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Composite Plug Milling via Wireline Reduces HSE Risks and Logistics on Location

Pre-set or off-depth composite plugs can cause significant non-productive time for a well operator. In the past, fracturing operations using a composite frac or bridge plug that has been pre-set or set off depth required a coiled tubing unit or workover rig to drill the plug out. Then, the well operator could resume the fracturing job or access the wellbore below the plug. However, as this paper demonstrates, composite plug milling via wireline using a tractor and a tractor-based milling tool is a faster, safer, and more cost-effective solution.

In a shale well located in the northern panhandle of West Virginia, a composite frac plug was set off- depth. Prior to mobilizing the tractor-based solution to location, the operator attempted pumping approximately 60,000 pounds of sand to sand-cut the off-depth frac plug out of the well. 

The sand cutting, though, did not work because perforations above the frac plug took the sand. Other tubing-based solutions required more mobilization time and complex logistics for rigging down and/or moving equipment on location. Therefore, the operator chose a wireline-based method for ease of operation, reduced HSE risk, and cost savings.

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Effective Application of Metal Expandable Packer to Prevent Gas Migration Issues, Leaks of Gas and Fluids in Annulus, Well Integrity Problems

This paper reflects the experience of applying modern technologies to prevent annualr gas migration, crossflows and pressures (ACP), well integrity assurance during the gas and gas condensate wells construction in South Tambeyskoye field.

South-Tambeyskoye gas condensate field is the largest in Western Siberia and the Arctic North of the Russian Federation. The development of this field is carried out by the JSC “Yamal LNG” (PSC “NOVATEK”) - one of the worlds leading gas and gas condensate exploration & production companies with the participation of Total and CNPC. Proved and probable reserves of the field according to the international classification PRMS are estimated at 926 billion cubic meters of gas and 30 million tons of liquid hydrocarbons.

At the South Tambeyskoye field, several field trial works (FTW) were carried out to prevent ACP on 4 wells:

- 3 production wells on Valanzhinsky deposits with reservoir pressures up to 350 atm.

- 1 production well on Jurassic deposits with reservoir pressures up to 820 atm.

Technology effectiveness comparison to standard methods has been conducted based on field trial results. Based on objectives achieved using modern technology, field trial works considered succesfull.

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Metal Expandable Annular Sealing Systems for High Pressure Open Hole Zonal Isolation and Stimulation

Metal expandable annular sealing systems were used in a 4 ½" completion as an effective high-pressure isolation method inside 6" open hole mudstone formation in the Foothills Basin of Colombia. Effective isolation proved to be historically difficult to achieve.

The operator was approached with a solid metal expandable sealing system with rotation capabilities as an annular barrier for a preferred cementless completion. The sealing system needed to be assembled on a full-bore liner able to deliver robust deployment with a high-pressure seal in a worse case washedout scenario. The deployment of the system consisted of one annular barrier placed above and one annular barrier placed below the mudstone zone.

Following careful job planning with the operator, the rotationally capable completion was deployed without any incidents. To achieve pressure integrity to set the metal expandable annular barriers, a ball seat sealing system was incorporated to allow the system to be closed and the annular barriers to be set.

After putting the well onto the pipeline, the client recorded a 52% increase in their expected produc-tion from previous wells. Successful results were accomplished as effective isolation was achieved and enhanced production was obtained because of the effective stimulation. This paper overviews the appli-cation, design, implementation and results of the use of new metal annular sealing systems in a 4 ½" completion as an effective high-pressure isolation method inside a 6" open hole, drilled in fractured sandstone and mudstone formations.

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Increased Production and Restored Wellbore Access Using E-Line Milling Technology, With Enhanced Health, Safety and Environment

An operator in Algeria, found that when attempting to put wells on production, the lock mandrels were found to be stuck in the nipple profile. All slickline attempts failed to retrieve the mandrel. When coil tubing was deployed, one plug remained stuck in its nipple, while the second one came off its seat only to get stuck inside a Side Pocket Mandrel, about 25m shallower. 

The sequence of pulling and jarring resulted in both fish necks coming apart, thus rendering all subsequent fishing attempts impossible. Therefore, a decision was made to attempt to mill the mandrels using the new e-line milling technology.

Another challenge was that the 2.562″ and 2. 75″ ID mandrels were made of 13 Super Chrome, and there was limited experience milling these types of completion components. Also, due to a rush mobilization, there was no time to execute a SIT. The solution presented consisted of milling first the mandrel outer sleeve, then milling the inner sleeve from the plug body which will cause the mandrel anchoring system to collapse.

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New Milling Solution for Flapper Valve Removal on E-Line in Dry Well Environment

In 2017, offshore North Africa, a well in a dry environment utilized a new application of e-line milling technology in combination with a specialized bit to mill out a failed flapper. This was the first time this special bit with the e-line milling toolstring was used to mill out a flapper valve in a dry environment. With this paper the author will describe the history behind the milling bit design, the actual operation and production improvements.

A gas well experienced a malfunctioning 7"x 4.56" 13 Cr. steel downhole flapper valve. Due to several operational challenges including limited well site access and temperatures over 150°C, there was a need for an alternative solution to mill the valve and allow access below it to re-perforate the well.

The operator's method of choice was an e-line tractor and milling assembly that had previous success in the same area in similar conditions. Furthermore, a new milling bit was developed that drastically reduces milling debris and eliminates potential fishing runs. Finally, heavier intervention methods like coiled tubing were not possible to mobilize because of the weather conditions plus the risk of reservoir damage if introducing fluids required to mill on CT.

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World's First Cement Replacement with Metal Expandable Annular Sealing on a Highly Laminated, Deep Water Injector in West Africa.

The field is developed within a complex environment, located within deep water and operated from a TLP/FPU facility. The wells are targeting 2 reservoir structures at 4000m TVD, requiring long and deviated wells to achieve field coverage. The reservoir is highly laminated with complex lithology requiring approximately 3:2 producers to injectors. 

Existing lower completion design utilizes a combination of cement and metal expandable annular sealing technology, to ensure zonal isolation and annular sealing (liner to formation) during the high-pressure stimulation and to ensure sealing over the life of well for zonal water shut off requirements. The oil reservoir is located approximately 20m TVD above a highly-pressurized water zone, making the oil producers challenging to drill and cement. Existing wells were drilled with a long shoe track into the water zone creating a possible flow path for the water to migrate along the annulus if annular sealing is not achieved.

As part of a global efficiency drive, the operator issued a challenge to the service industry, to reduce the DRILLEX of these wells whilst maintaining the beneficial productivity index that has been achieved within the highly heterogeneous carbonate field, being prone to asphaltenes. One of the implemented solutions wascement replacement across the reservoir. The benefits of this solution impacted several areas; it removed the need for drilling 100m of rat hole, under reaming of the 6 ½″ hole, clean out of the 6 ½″ hole and most significantly, eliminating cementing of the 4 ½″ liner. This led to a substantial cost savings and reduction of rig time and because it simplified the operations, the operational risks were also reduced.

The scope of work to deliver the solution included the design, development and qualification of the metal expandable annular sealing system. The project included validation of both sealing and anchoring of the cement-less liner within the open hole. The solution was also required to maintain the synergies with the perforation, acid stimulation and diversion techniques to achieve the required Productivity Index (PI) and Injectivity Index (II). The first deployment was within a well that was converted from producer to water injector. This would help validate the technology for further deployment on oil producers. The lower liner with the metal expandable annular sealing system was deployed from the rig whilst the activation (expansion) and subsequent acid stimulation were completed offline. Production and injectivity data were analysed and compared to the PI / II to the prior cemented and perforated well designs.

This paper will discuss the project scope of work, first deployment of the metal expandable sealing system, data analysis and an estimate of the risk and cost reduction delivered.

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E-Line Intervention Enables Operator to Design, Manufacture A New Customized Bit to Mill Out Isolation Valve in Record Time and Enable Early Production from Well

A well in the Panna-Mukta-Tapti Joint Venture (PMT JV) was completed using an isolation valve as the method of isolating the reservoir whilst running the completion into the well. Mechanical failure to open the valve was not anticipated as the isolation valve had a successful history in the JV with no failures in the last 10 years. However, in this well, the isolation valve failed to open. After spending multiple days attempting to open the valve and diagnosing the cause of the failure, it was concluded that the isolation valve was mechanically stuck.

Further evaluatios of solutions incorporating Coil tubing (CT) and e-line interventions concluded that standard milling operations would pose additional challenges for the well due to the design of the completion below the isolation valve. 

Subsequently, a unique, star shaped milling bit was designed and manufactured to enable milling of the isolation which was smaller than 2.56" SSD and landing nipple present below the isolation valve. This was required to ensure future access for interventions through the SSD and landing nipples is not compromised and milling out the coupon from the flapper isolation valve does not get stuck in the smaller ID completion profile below it.

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Pushing Operational Limits in Challenging Perforating Environments

The W field located north of the coast of East Malaysia, Malaysia in approximately 100 meters of water. Five dry gas wells, W1 through W5 were drilled and cased between Q1 and Q4 2016. The well depths fell between 3700 meters and 3825 meters measured depth (MDDF), 2with bottom hole temperatures as high as 180 degrees centigrade and formation pressures of 6500 psi. In addition, the wells were expected to be sour with 140ppm H2S and 20% CO2.

Originally the wells were planned to be completed with slotted liners, however this was proving to be problematic as it limited well control options and a safer solution was needed. An alternative un-cemented liner was run and it required to be perforated. 

TCP (Tubing Conveyed Perforation) and CTCP (Coiled Tubing Conveyed Perforation) were the logical choices, however after some considerable discussion it was agreed that wireline conveyed guns employing friction reducing rollers and tractors had the potential to save considerable rig time while satisfying all safety concerns. Detailed planning and simulation for this complex operation was required, the operator and service provider formed a strong technical alliance to achieve the objectives.

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Hydraulic Fracturing in Horizontal Depleted Gas Wells - Challenges, Solutions, Lessons Learnt

In recent years, horizontal drilling has become increasingly important to the oil and gas industry to enable efficient access to complex structures and marginal fields and to increase the reservoir contact area. New technologies have emerged during this time to address post-drilling intervention challenges in such wells. 

However, complexity of operations in horizontal wells is much higher than that of the vertical wells; therefore effectiveness of the selected technique has a major impact on the operational success and economics. In depressed market environment, economical and operational effectiveness becomes even more important especially when it’s down to complicated, challenging projects that require not only large investments but also simultaneous and continuous utilization of multiple resources, technical disciplines and assets. 

This paper reviews and compares different ways of horizontal multizonal well preparation for hydraulic fracture stimulation using plug & perf technique in challenging downhole conditions - differential pressures over 15,000 psi, presence of depleted zones complicating cleanout and milling operations between the frac stages, depth control issues.

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Innovative electric-line pipe cutting system utilized in subsidence workovers with casing in extreme compression

This paper documents a job campaign encompassing seven operations that were performed over a 6-month period in the Kuparuk River Unit, Alaska. The subject wells had all been selected for workover due to subsidence issues and the production casings in each of the wells were in varying conditions, ranging from slight tension to severe compression.

Many previous subsidence workovers had utilized drill-pipe conveyed cutters which required the casing to be in tension to ensure a quality cut. In order to get the casing in tension, a multi-step process was required. First the blowout preventers (BOP) and tubing heads had to be removed. That was followed by a controlled growth of the compressed casing after which the casing was then stretched and re-landed in tension. The excess casing was then cut off, and, finally, the BOPs were re-installed and tested. This entire process could many times take over 24-36 hours.

In an effort to reduce rig time and ultimately workover cost, research was performed to find a cutter that could cut production casing in compression. The one chosen was an e-line conveyed cutter that could be run in conjunction with the cement bond log required on subsidence wells prior to the cut. This tool has a history of making cuts in casing that was under compression, but had yet to be vetted in the compression ranges associated with severe subsidence damage.

This innovative technology can be used in other wellbores where a quick, precise, and non-explosive casing cut is preferred, but most importantly, can be used with pipe in compression. This solution proved successful on six out of the seven cuts conducted in this campaign and is a cost-effective alternative to the aforementioned, conventional pipe cutting method. The campaign resulted in a rig time savings of approximately 18 hours per well.

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Efficient installation of a modular straddle system for deep water gas or water shuts offs

A well with a high gas-oil-ratio (GOR) was experiencing gas coning due to the recycling of injected gas. A gas shut off was recommended to improve gas handling efficiency due to the constraints on surface processing capacity. The strategy was to install a 138 m, retrievable straddle assembly across a zone spanning from 2572 m measured depth (MD) to 2719 m MD in the 5 ½ open hole gravel pack (OHGP) screens.

The client’s considerations included coiled tubing (CT) and slickline. It was also necessary to be as efficient as possible to keep time and costs down. Based on these considerations, the operator decided to use an electric line (e-line) tractor combined with a hydraulic stroking tool for its high reliability. The stroking tool also provided the benefit of delivering the required force at the exact point where it was needed downhole as compared to coiled tubing, which would exert the force from the surface.

The complete straddle packer assembly was successfully installed in 17 runs without any nonproductive or lost time incidents. As a result of the intervention, gas production was greatly reduced and oil production was returned to normal levels. The operation was so successful that the client saved nearly 30 days on an operation that was planned for 45 days.

Due to the success of the initial operation, the client decided to execute several other, similar water and gas shut off operations in the field replicating the same methodology. This paper highlights the methodology used and the cost and HSE benefits provided by selecting the e-line solution with the tractor and stroking tools to perform the gas shut off. The paper will also discuss the details of the job planning as well as the execution of the operation, marking a first in this West African country.

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Evolution of Ball/Baffle Milling in Karachaganak Field Using Tractor Milling Technology from 2011 to Date

New wells in KPO are completed as multistage frac completions utilizing up to ten stimulation sleeves activated by a ball landed in a respective seat (called a baffle) installed inside the sleeves. The objective since the beginning was to mill balls and baffles in the horizontal section improving the safety of the operation while minimizing volume of fluid injected, execution time, costs, and clean-up time.


The initial approach was to use coiled tubing. Using coil to mill balls and baffles was not optimal, as the milling performances were difficult to replicate well after well. Additionally a significant amount of fluid was injected into formation together with some debris causing formation damage and making clean-up a long and costly process. An alternative option of milling utilizing robotic technologies was investigated as a viable solution for improving our performance. Therefore, the experience gained by KPO on milling with tractor in multistage frac completion is unique worldwide, and did add a lot of value to the wells delivered to production

This paper describes the evolution and modification done to tractor milling approach, particularly:

  • Yard tests performed before implementing the operation in the field. No field deployment application took place before yard test outcomes were completely satisfactory.
  • Results of the tests and modifications done to the tools as a result of the tests performed in the yard.
  • Performance during field job execution, lessons learnt during each application, and how those lessons learnt influenced design modification of the tools and milling methodology.

Thanks to a close collaboration established between KPO and Welltec, all objectives were accomplished with repeatable performance. Recently, up to nine balls and baffles corresponding to the entire horizontal section have been milled with a tangible benefit in terms of production, reducing clean-up time and emissions and improving safety.

Even though the initial target was achieved, KPO believes there is still room for improvement and optimization. This will be done in the near future following further dedicated yard tests with positive results.

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Unique Milling Bit Deployed via E-Line Intervention Enables Operator to Achieve Early Production

This paper presents the significant benefits accomplished from the utilization of robotic, electric-line (e-line) intervention to mill out a malfunctioning flapper valve versus the use of coiled tubing (CT). In addition, it will discuss the flexibility and control features of e-line based, intervention technology towards addressing short lead time and design modifications required to meet dynamic well challenges.

On the West Coast of India a well was completed using a flapper valve as the method of isolating the completion while being installing it into the well. A standard practice in the field, the flapper valve has been utilized successfully for a decade without any failures. Hence, during the current operation, contingencies to overcome a mechanical failure to open the valve were not on board. And unfortunately, in this particular well, the flapper valve failed to open as per SOP.

After multiple days spent on attempting to cycle open, attempts were then made with slickline to determine if debris accumulation was an issue. When this proved false, it was concluded that the flapper valve was mechanically stuck.

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A New Electric Line Downhole Jetting Tool Accomplishes Sample Collection and Screen Clean-Out to Restore Production

A North Sea well was drilled and completed as a sidetrack with a 4 ½" liner set using open-hole sand screens (2x12m) in the toe and swell packers for isolating the production intervals. Due to poor productivity and injectivity, the well had been shut-in. It was suspected that the completed interval had been filled by particles (mainly barite) from different mud types that were suspended or settled in the completion fluid placed both inside and outside the screens.

Due to multiple uncertainties regarding the fill, it was desirable to perform a drift run to determine the hold-up depth (HUD) and collect samples there. The operator decided to apply a modified version of a known electric-line (e-line) suction tool. 

The service company modified the tool to include a set of unique valves which would be able to store and preserve downhole liquid and solid samples, enabling the operator to retrieve and analyze the debris. This would then allow them to subsequently determine whether a planned chemical was the best possible treatment solution to remediate the suspected screen plugging.

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Electric-Line Milling Operation on Tree Master Valve of a High Surface Pressure Well Enables Well Control

This paper presents the success story of an innovative milling operation on a stuck-closed tubing master valve performed with electric line technologies. This field application has resulted in restoration of well accessibility, enabled well control, and saved costs related to rig intervention. The paper also documents lessons learned and recommends proper operational procedures related to future similar rigless operations, specifically with regards to well control and barrier philosophy.

A stuck-closed surface valve in a live well is treated with extra caution as it presents a serious and challenging well control issue. Such a situation often calls for immediate intervention to restore well accessibility and reestablish well integrity barriers. 

The stringent well control requirements of the oilfield operator make the operational design and corresponding job execution even more challenging. In this case, Well-A is a land based vertical oil well on which the master gate valve was stuck and non-functional in the closed position. The pressure bellow the valve was last measured to be 1200 psi, a relatively high shut-in wellhead pressure compared to other offset producers in the same field. 

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Subsea Coiled Tubing Acid Stimulation Operation Using CT Tractor in Angola

An Angolan operator needed to perform a coiled tubing (CT) acid micro-wash stimulation on a subsea sand screen completion in order to improve production. The CT simulation showed that the coil would not reach the objective, which was the bottom screen, even with friction reducers, without the assistance of additional forces. The operator chose to deploy a downhole tractor to provide a pulling force to achieve the desired depth. However, this horizontal well had debris which prevented reaching the objective and required changing strategies to accomplish the job.

A downhole tractor can be powered by pumping fluids down the coiled tubing, driving a turbine which powers the hydraulic systems in the tractor. The drive fluid will then pass through the tractor and out the bottom of the tool to provide the treatment.

Surface testing is performed prior to the job to determine at which pumping rate the tractor will be engaged and disengaged. This testing is performed with and without treating nozzles to gauge tool performance and expected pumping rates for tractoring and treating.

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Benefits of Cutting Pipe under Compression in Deepwater Rig Operations

This paper will describea tubing cut operation carried out on a deepwater rig without having to first perform the usual, time consuming rig operations to work tension down to the target cut depth. Avoiding this standard procedure was achieved through application of a unique "Mechanical Cutter based Cutting Pad platform" (MCCP). 

Utilization of this technology enabled the operator to avoid having to unseat the tubing hangar and expose non-shearble across BOP and loss functionality of Surface Controlled Sub-surface Safety Valve. The other add-on benefits from this system is reducing number of wireline in the deepwater environment.

Prior to introduction of MCCP, all others technologies recommendedthat the pipebe placed in tension achieve a successful cut. MCCP technology allows the flexibility of effective and efficient tubing cut with string in both tension and compression which is highly desirable in deepwater intervention. The is achieved as the tool incorporated grinding of tubing surface which enables a smooth cut.

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Next Generation Annular Barrier Verification System

The cost savings that are possible by sidetracking existing well bores make the drilling and completion of ultra slim lateral wells very desirable. Obtaining image logs from horizontal wells, less than 6” diameter, has always been a challenge, because the size of conventional borehole imaging tools that currently exist on the market are simply too large. In addition, conventional deployment methods limit efficient rig time utilization and ultimately lead to higher cost. 

New conveyance and logging technology from Welltec® (the Well Tractor®) and Weatherford (The Compact Micro Imager – CMI) allows operators to obtain excellent image logs in slim wells as small as 3 inches in diameter. Image logs are required to properly understand fracture details and to help in future drilling and completion decisions.

This paper describes the logging operational experience of the CMI and the world’s first slim hole imaging logs in Saudi Arabia deployed by the wireline tractor 218XR (XR: Extended Reach) in an open hole horizontal section.

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Intelligent Completion or Well Intervention Robot?

Well interventions represent one of the main operational expenditure (OPEX) in the O&G industry, especially in offshore fields. Historically, high cost of semi submersible rigs or drillships and long time to acomplish them have restricted the offshore well interventions. Based on this, the O&G industry has developed technologies in order to perform offshore well interventions in an economically viable way. Riserless well intervention (RLWI), intelligent completion (IC) and intervention robot (IR) are relatively new technologies and recently gained importance in the O&G industry.

Therefore, this paper details the operations and values of IC, RLWI, and IR technologies. Moreover, we analyze and compare those technologies, confronting them against the known production loss problems that require well intervention.

The objective is indicating which technologies are feasiable for the future well intervention on subsea wells.

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Optimization of the Operation Time Required for Data Gathering Requirement in Extended-Reach Drilling Well by the Use of Open Hole Tractor in the United Arab Emirates

Gathering of wireline data in Extended Reach Drilling (ERD) wells is still not a standard process, complicated even more by inclination and step out. This paper presents a case study of recording logs conveyed using an open hole tractor in a highly deviated section. The challenge was made more difficult because Water Based Mud (WBM) was required to allow the full suite of planned logs. The operation time that can be saved is up to four days.

The 8.5 in. pilot hole was designed based on the target and the sidetrack points for the mother hole. The inclination of the pilot hole was 63° and the wireline accessibility simulation based on offset friction factor showed that the open hole was not 100% accessible with Wireline Conveyed Logging (WCL) string. 

Therefore, an open hole tractor was selected to reach the required point. To minimize the risks for the logging operation, a six blade Polycrystalline Diamond Compact (PDC) bit, Rotary Steerable System (RSS) and Logging While Drilling (LWD) were used in the pilot hole to make a smooth trajectory and confirm wellbore conditions.

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Development and World's First Field Deployment of 2.125? Tridem Coiled Tubing Tractor for Extended Reach Open Hole Horizontal Wells with ESP Completions

Coiled tubing (CT) tractoring technology has come a long way since its introduction in 1996. Numerous extended reach wells have been successfully stimulated by CT using large CT tractors (2.5-in–4.7-in outer diameter [OD]). Still, technology had to be improved for wells where completion inner diameters [IDs] were restricted due to artificial lift installations or other reasons. The development and field trial of a slim CT tractor with improved gripping and applications envelope are summarized in this paper, along with lessons learned.

A CT tractor with a 2.125-in OD was developed for cost-efficient rigless. Previously, CT tractors able to pass restrictions in electric submersible pump (ESP) installations with bypass arranged by Y-tools of 2.38-in–2.44-in ID were not able to develop the required pull force to convey the CT string to the target depth (TD) while operating in open hole environments with uneven ID distribution.

A hybrid tridem well tractor was developed based on hybrid downhole power generation and an existing wireline tractor. In order to provide the required pull force and contact to the formation, three wireline tractors were connected into a single tool.

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Successful Deployment of Tractor Conveyed Perforation in a Horizontal Well: Designing, Execution, Results and Lessons Learnt

Well X is a horizontal oil producer in AB-3 formation of the B field situated in the RJ-ON-90/1 block of Western India. Intervention in a horizontal well is inherently challenging, but the complex completion equipment of this well imposed additional challenges due to multiple ID changes along the well bore. 

The 8.5" OH section is completed with Inflow Control Device (ICD) screens and Swell Packers, middle completion consists of Packer and a Reservoir Control Valve (RCV) section set in the 9-5/8" production casing. Finally with 4.5" production tubing – and the production packer, upper completion was lowered but end of tubing was lying 8 m above the RCV section exposing 9-5/8" casing section also during any intervention.

After the initial completion when well was put online, it couldn’t flow naturally and was activated with nitrogen. Post activation it was observed that a well with 500 m of clean sand along the lateral section and productivity index (PI) of 150 b/d/psi was flowing with a PI of ~ 10 b/d/psi which also was not sustained and well was put on artificial lift. After attempting various stimulation techniques and correlating with offset wells, it was decided to perforate the screen section of the horizontal.

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Crown plug pulling performed as riserless light well intervention in the gulf of mexico - overcoming the challenges

Having a reliable backup plan is vital to ensure successful riserless light well intervention (RLWI) operations. This paper will present learnings from a subsea operation where the contingency solution was engaged to resolve a critical issue. The need for thorough back-up planning will be discussed along with the planning process, execution and lessons learned.

Methods, Procedures, Process:
Crown plugs are conventionally retrieved using slickline jarring; however, high performance shifting tools on electric line are gaining foothold due to their ability to apply a focused, axial force downhole. Up to 33,000 lbs of force can be exerted through the use of a bi-directional, hydraulic ram. These electric line (e-line) stroking tools can be fitted with various shifting or pulling tools for lightweight mechanical services. For subsea interventions this is good news as space is particularly limited on vessels, which means that intervention solutions that simplify logistics by reducing equipment and crew is sought after.

Results, Observations, Conclusions:
The case to be presented is from a RLWI operation in the Gulf of Mexico where a crown plug had failed to release. Slickline (SL) was the first method to be put into action. On the first attempt 148 jars failed to retrieve the plug, then another 199 jars yielded the same result. It was believed that these repetitive attempts had broken the seal, resulting in saltwater inflow that had created hydrates. 25% Methanol Ethanol Glycol was pumped while jarring, but eventually the contingency plan was activated. This consisted of a hydraulic stroking tool, which successfully managed to remove the upper crown plug and thus allowed the operation to continue without further downtime. The operator would have had six months of deferred production (being unable to open the sleeve to the upper zone) if the crown plug was not retrieved as they would have needed to wait for a riser. This underlines the importance of having an adequate contingency solution to overcome the challenges in riserless interventions. The benefits will be increased operational efficiency and reduced overhead costs.

Novel/Additive Information:
This was the first operation where a crown plug was pulled during a RLWI operation with an e-line bi-directional stroking tool. The tool in this case was capable of 33,000 lbs of force; however, since the execution of this operation, further developments in engineering have led to a redesigned stroking tool with the ability to apply up to 60,000 lbs of force. What opportunities that opens up for RLWI operations will also be presented.

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Milling faulty lubricator valve using innovative e-line conveyed core bit

Field A is a gas field located in Malaysia-Thailand Joint Development Area. As the field matures after 10 years of production, the number of idle gas wells has been increasing due to various issues such as low tubing head pressure, mechanical problems and sand fill.

Currently, the operator has embarked on an aggressive, reactivation campaign to restore production through interventions. Well A became idle in January 2013 due to unknown reasons and was selected as a pilot well for the re-activation campaign. Tubing Retrievable – Surface Controlled Subsurface Safety Valve (TR-SCSSV) cycling and Critical Device Function Test (CDFT) were performed successfully, but did not impact the production. In August 2013, lubricator valve (LV) diagnostics were performed using a Lead Impression Block (LIB) tool which indicated that the lubricator valve above the TR-SCSSV was only 80% open. As such, this malfunctioning lubricator valve (LV) prevented any future interventions for diagnostics, zonal isolation or the addition of perforations in order to fulfill the objectives of the idle-well reactivation campaign.

An in-depth, internal review had been conducted previously to evaluate all the available solutions in the market from both a technical and economic perspective. To enhance the chances of success, an innovative e-line conveyed core milling bit solution was selected for the pilot job in well A to restore full access to the well.

A customized solution using a 4.55 inch milling core bit run on e-line managed to successfully mill the malfunctioning lubricator valve and restore access to the well with substantial cost savings and lower risk compared to coiled tubing (CT) operation. Both milled coupons were retrieved with the aid of a catcher and brush combination designed into the bit .This managed to restore the access for the future intervention, zonal isolation and additional perforations in this well.

This paper shares a detailed case study of Well A in terms of technology selection, operation execution, lessons learnt, and future recommendations. It is evident that e-line conveyed, core milling bit technology is technically and economically feasible to mill malfunctioned lubricator valve, thus eliminating the need of expensive solutions such as CT or rig intervention.

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New mechanical pipe cutting capabilities on electric line

This paper will present several case histories on the subject of mechanical pipe cutting on electric line (e-line) as well as the operational steps selected to make the pipe cuts. A description of a new pipe cutting tool together with lessons learned to improve future operations will also be discussed.


A new approach that enables simpler well completion and higher recovery

Focusing on a new way to complete and maintain wells, this paper will explain how a newly developed completion approach enables safer, more sustainable operations with higher production and recovery rates from a simple, durable and cost effective well construction.

Methods, Procedures, Process:
The approach, here referred to as the flex-well, concentrates on simplicity while providing all the components an operator requires to design and construct a completion that is fit-for-purpose; it can be as minimalistic or as intricate as the operator requires in order to accomplish maximum reservoir drainage. The flex-well has been engineered to provide a low total-cost-of-ownership solution that meets global operators’ current and future drilling, deployment, and production
challenges. The flex-well integrates intervention solutions through a full-bore completion designed for easy access and proactive adjustment.

Diagnostic solutions that convey information to surface through wireline data retrieval allow operators to achieve a detailed understanding of well characteristics without permanent cables to surface. This understanding allows for better decision making to optimize and manage the reservoir for maximum recovery throughout the life of the well.

Based on the operators data driven decisions production and stimulation valves can be adjusted through wireline interventions, eliminating the need for control lines to surface. With no lines to surface the well design offers complete flexibility for inclusion or addition of multilaterals for infill drilling.

Results, Observations, Conclusions:
The benefits, simplicity and design flexibility of the concept makes it applicable for operators across all resource plays, conventional and unconventional. However, some factors and conditions do enhance the attractiveness of the solution, such as when traditional cementing is challenged, when high-pressure differentials are present, or when full-bore liner design is desired.

Novel/Additive Information:
This new way of designing and intervening in oil and gas wells offers the industry a safer approach that results in fewer people required offshore, simpler procedures and operations, and less equipment deployed for shorter time.

Find the full paper at https://www.onepetro.org/


Spotting cal-acid scale dissolver precisely using am ingenious tweak on a proven electric line riserless light well intervention method

CaCO3 scale build-up may cause severe production restrictions. A common resolution is electric line (e-line) clean-out with bailers built into the toolstring to capture the debris while milling. This paper will provide details of an innovative tweak that allowed an offshore operation to continue despite the presence of CaCO3scale. The paper will also discuss the equipment and Riserless Light Well Intervention (RLWI) method to derive valuable lessons learned for future operations.

The operation took place in the British shelf of the North Sea. A subsea well was facing severe scale issues that were threatening to stop production. From the beginning, it was the plan to perform the operation as a RLWI from a vessel. During the initial drift run, it was discovered that the CaCO3 scale had become so severe that it would not be possible to run the e-line milling solution as originally planned. The team needed to remove ~15 ft. of scale in order to accomondate the clean-out toolstring below the subsea tree before the operation could continue. Standard dump bailers were not available on the vessel and, as weather prevented the flying of equipment to the vessel, the team worked together to quickly contrive a readily available solution that would allow Cal-Acid scale dissolver to be spotted precisely and safely at the holdup depth.

The solution became to modify the clean-out tool by removing the drive shaft and mill bit, introduce check valves, and pre-load the bailers with Cal-Acid. This enabled the tool to act as a dump bailer with the Cal-Acid being displaced out of the pump ports and onto the scale. The Subsea Intervention Lubricator (SIL) had been pre-filled with Cal-Acid and, once the milling tool was activated in the SIL, the acid circulated into the bailers, which eliminated the need for any surface handling. The tools were then run to the holdup depth and the Cal-Acid unloaded. This was performed 16 times resulting in ~ 150 L of Cal-Acid being spotted around the scale build-up. A subsequent run with gauge cutters confirmed that the Cal-Acid spotting had been successful and access for the remainder of the operation had been achieved.

Novel info:
The innovative use of readily available tools, modified to a bespoke application, allowed the operation to continue, resulting in significant time and cost savings, and the concept of filling the bailers in the SIL made the operation inherently safer through reduced manual handling and recovery of sub-sea equipment.

Find the full paper at https://www.onepetro.org/


New advances in mechanical engineering enables pulling forces of up to 60,000 lbs. - experience gained from offshore norway case stories

This paper will present an improvement in engineering in the form of a hydraulic stroking tool with the ability to apply 60,000 lbs. of force. The tool has already been applied offshore Norway and lessons learned from these recent operations will also be disclosed.

Methods, Procedures, Process:
In one operation, a plug was accidentally set across the christmas tree and blowout preventer (BOP), effectively eliminating the christmas tree as a well barrier element, and constituting a serious HSE risk. Conventional solutions failed to release the plug due to an insufficient pull force and then a failing jar. In another well, the setting tool had malfunctioned resulting in a partially set plug and a stuck tool. Repeated attempts with heavy duty fishing equipment had damaged the fishing neck, further complicating the fishing operation as the setting tool had failed before it could break the stud connecting to the plug.

Results, Observations, Conclusions:
The high performance of the recently developed stroking tool turned out to be the correct solution for both of these demanding operations. In the first well, it was estimated that the force required to shear the plug from the setting tool would be 43,300 lbs. The operation was completed in three runs with no misruns, which saved the operator from prolonged exposure to HSE risk including well control situation. In the second well, the force required to shear the stud and free the setting tool was 40,000 lbs. Two release devices were combined in the toolstring, one below the hydraulic stroker and one below the cable head, in order to allow further contingencies to mitigate risk and increase safety. After four attempts the shear stud parted, thus completing the setting sequence and freeing the stuck setting tool. The operator got the well back on track, saved five days of rig time and avoided the costs of a workover rig.

Novel/Additive Information:
The case stories in this paper constitute the first jobs performed with the new tool. Two important features are reduced HSE risks and increased operational efficiency, which will also be captured in the paper.

Find the full paper at https://www.onepetro.org/


Hostile environment electric line well interventions optimize operations in Kazakhstan

Electro-hydraulic robotic tools that perform well interventions on electric line (e-line) have come of age over the past 10 years and can now be used to accomplish tasks previously done with the use of jointed pipes and/or coiled tubing conveyance system.

Examples of such tasks are downhole milling, shifting of stimulation sleeves, etc. Surface real time monitoring and control features are required to ensure that such tasks done by robotic tools are successfully achieved with high accuracy. As the demand increases to use this type of powered devices in a more hostile well environment, service companies have developed technologies to expand their operating range.

Starting from late 2013, the robotic technology solution has been used in KPO horizontal sour wells to close stimulation sleeves when required for reservoir fluid management, to convey perforation guns, to convey production logging tools and to mill frac balls and ball seats. This paper will present four case histories of the robotic technology application in the Karachaganak field. It will discuss the advantages of the technologies, the challenges and the future improvement required to further optimize the field operations.

Find the full paper at https://www.onepetro.org/


Combined electric line milling and cleanout to eliminate fluid costs for multi-stage frac preparation in southeast Saskatchewan

Clients utilizing Coiled Tubing (CT) for straddle frac operations in multi-stage horizontal wells often encounter cement stringers preventing the frac bottomhole assembly (BHA) from reaching plug back total depth (PBTD) and the packer from sealing to the casing wall. This paper presents the learnings from a >90 well campaign of preparing for fracking operations using an electric line (e-line) milling and clean-out tool. The wells were mostly cemented, 4.5″ liners with frac sleeves. This technique reduced frac preparation costs in the cemented wells by approximately 30%.

Methods, Procedures, Process:
The common practice in Southeast Saskatchewan (SE Sask) is to perform a “well prep” operation prior to the frac equipment’s arrival to the well site. A CT unit equipped with a rotating scraper/mill—and associated fluids—is used for the clean-out, adding to the logistical coordination and well costs. Fluid has several costs associated with it: the cost of the fluid/water itself, heating for winter operations, trucking and disposal. However, “well prep” is considered “cheap insurance” by most operators working in SE Sask compared to the potential costs of a waiting frac crew.

Results, Observations, Conclusions:
An operator in SE Sask has had success with an alternative clean-out solution to replace the use of fluid for well preps by introducing an e-line method consisting of an electric milling & clean-out tool with a casing collar locator (CCL). The mill is conveyed by e-line tractor and is equipped with a scraper mill to confirm the PBTD and ensure that there is no cement debris or sheath present that could negatively affect the frac operation. Various bailers can be added to collect the cement debris in the same run and ensure it is removed from the wellbore. In combination with the clean-out service, a CCL is deployed and logged to surface to pinpoint the exact sleeve location to be
referenced during the frac operation. This new, efficient clean-out solution has proved slightly more time-consuming (~3-5 hours) but yielded significant cost savings of approximately 30% per well of prep costs. These savings come from using e-line equipment, eliminating fluid costs and offering inherently safer operations with a low carbon footprint.

Novel/Additive Information:
Moreover, the paper will discuss the future applicability of this ‘additional application’ for pre-logging runs as a means to reduce total completion costs in cemented wells. This is achieved by using the e-line milling tool as a pre-run for casing inspections or cement evaluation logging.

Find the full paper at https://www.onepetro.org/


Successful utilization of e-line tractor in horizontal, high temperature gas wells

Growing gas resource exploitation in Saudi Arabia has increased activity in drilling deep, high pressure gas reservoirs with marginal to low permeability. Such wells generally require stimulation operations to induce production. To increase the reservoir contact area, a significant number of wells are constructed with long reach horizontal sections.

Multistage fracture operations are primarily conducted using plug and perforation technology to establish reservoir connectivity and production. The stimulation work involves multidisciplinary teams conducting simultaneous operations in a limited workspace and time. The primary well intervention challenges include the following:

  • Effective deployment of cement and casing inspection tools in the horizontal section
  • Safe, reliable, and efficient technology to convey the perforating bottomhole assembly (BHA) to the target depths in the long horizontal section during some stages of the plug and perforation operations
  • Available, reliable, and readily deployable contingency perforating option for plug and perforation operations

High-pressure, high-temperature (HPHT) horizontal gas wells have traditionally been challenging for performing tractor operations because of reliability issues. Recent technical improvements have enhanced the operating range of the tractor, enabling more consistent and dependable operations in these environments.

Based on the experience of conducting several plug and perforation stimulation jobs in Saudi Arabia, the electric-line (e-line) tractor has proven to be a reliable and consistent well intervention solution. The tractor-conveyed cement evaluation tools have produced high quality interpretable data used to design the multistage fracture job. Post-fracture diagnostic work has also been successfully performed in the horizontal sections to evaluate tubular integrity, providing valuable information for future fracture design. Moreover, tractor-conveyed perforating has proven to be an effective solution for conducting stage-1 toe perforations in comparison to other options from several aspects.

The option of contingency perforating in a closed system without fluid injectivity into the previously perforated stages has helped to maintain the continuity of operations. Successful tractor interventions have been performed in wells with more than 3,000 ft of horizontal sections, total depth (TD) of more than 17,000 ft, temperatures greater than 325°F, and pressures greater than 10,000 psi. This paper describes how the state-of-the-art technology has helped to meet the technical objectives of, and had a positive effect on, large rig-less production enhancement.

Find the full paper at https://www.onepetro.org/


Downhole machine with electric wireline technology

This paper will demonstrate technology to do downhole interior reconstruction in an older well design to create larger tool access using wireline technology. The intent is to document the applied technology and the value creation.

The methods described were actual field operations demonstrating the successful application of the technology in a mature field. This paper will describe the history, background and challenges of a well in this mature field and the subsequent application of alternate technology to overcome those challenges and maintain the asset as a viable, producing well. Due to the availability of downhole tools and services to solve an immediate problem in a well, the need to reconstruct the existing wellbore interior to create larger access for example, becomes inevitable in many cases. Such was the case on offshore wells in Indonesia where the inner diameter size of the downhole accessories forbid tools to reach the lower targeted depth.

Following the success of the first nipple milling in the world at an Operator’s field in Indonesia in 2009, another 12 wells had applied the same intervention technique at one field location and many other wells in various part of the world. The advantage of wireline nipple milling includes level of precision in milling, new smooth finishing of treated downhole accessories or completions, minimum cuttings left downhole, minimum volume of liquid required, small footprint required during operation and speed of milling operation that could be less than 2 hours even in small restriction such as 2.6 inch inner diameter. This paper presents the up to date achievements, case histories, challenges, best practices and technical aspects of the aforementioned milling system as well as similar challenges can be solved using similar technique.

Find the full paper at https://www.onepetro.org/


Multiple tubing cuts in one run improve operational efficiency

In this paper, the author presents a case story from the Middle East in which multiple tubing cuts were performed using a new, non-explosive, electric line (e-line) conveyed tool on the same run in the hole. As this was an outstanding achievement, never accomplished before in the region, the paper discusses the planning, the operation, the achievements and the lessons learned.

Methods, Procedures, Process: A common practice for workover operations is to remove the existing completion and replace it with a new completion, either the same or sometimes with improved components. One of the steps required to pull the completion in this case is a run to cut the production tubing in one or more places prior to pulling the completion from the wellbore. A common practice is the use of an e-line cutting tool. Conventionally the best practice for this e-line tubing cut operation is to keep the pipe/casing in tension while performing the required cuts. This practice prevents pinching of the cutting blades and ensures higher chance of a successful cut for the operation.

Results, Observations, Conclusions: An operator in the Middle East has experienced success in performing multiple tubing cuts in a single run on an offshore well using an e-line deployed electric over hydraulic cutting tool with tubing in compression.

Novel/Additive Information: Moreover the paper reviews test results from a new style of machining arms and discusses how this technology is enabling an operator to perform rigless cuts to eliminate the cost of rig time to be more efficient, safe and cost effective.

Find the full paper at https://www.onepetro.org/


Fishing slickline using wireline-deployed robotic technology for mechanical intervention

Over the last two decades, advances in robotic technology in the form of wireline tractor devices, Well Stroker tools, and well milling and cleaning devices have brought to the industry a broad range of applications in deviated and horizontal wells.

These technologies often present cost-effective alternatives to proven methods, providing in many cases more precise control of operational parameters and greater access to highly deviated well configurations. Slickline cable deployment as a means of well intervention operations has long been an industry standard for a wide range of applications. Bottomhole assemblies (BHA) can be designed and configured to set and retrieve a broad variety of valves and plugs required for numerous completion and well maintenance procedures.

In general, the setting and retrieving of such components requires a jarring force be applied, either up or down depending on the particular application, to overcome the shear strength of pins inserted in the valves and running or pulling tools to effect the action. In the case of slickline deployment, this force is applied from surface and transferred downhole via cable tension to the jarring device, which can be mechanical or hydraulic depending on the configuration. In deviated wells, the force that is transferable at depth is reduced because of friction contact between the cable and the casing or tubing and other factors, such as fluid weight and viscosity and wellbore debris can further impede the efficient and safe transfer of this force downhole.

These variables are sometimes difficult if not impossible to determine and model for, and changes in downhole or surface conditions during the operation can have substantial impacts on its success. This paper demonstrates a novel approach to fishing a slickline BHA while maintaining control of the slickline cable at surface. A Well Stroker tool was deployed by wireline tractor to assert the necessary force required to shear a 5/16-in. brass shear pin on an SB running tool attached to the bottom of a slickline tool string. Several procedural and operational modifications resulted in a successful operation.

Find the full paper at https://www.onepetro.org/


New method for milling flapper valves on e-line in dry environments

In 2012, for the first time ever in North Africa, a well in a dry environment utilized e-line milling technology to mill out a failed flapper. With this paper the author will describe the actual process from preparation to completion of a world’s first operation.

A gas well experienced a malfunctioning 74.56 13 Cr. steel downhole flapper valve. Due to several operational challenges including limited well site access and temperatures over 150°C, there was a need for an alternative solution to mill the valve and allow access below it for future well interventions. Furthermore, due to the fact that the well was a gas producer, there was a need to avoid, or minimise introduction of any fluids in the well. The method of choice was an e-line tractor and milling assembly. Because of the size of the offshore platform this was the only feasible solution. Heavier intervention methods like coiled tubing were not possible to mobilize because of the weather conditions plus the risk of reservoir damage if introducing fluids.

The e-line tractor conveyed the toolstring to target depth (2,916 m MD) where the e-line milling tool was activated and milled through the flapper valve in approximately 40 minutes. After the completion of the milling phase of the operation, another run was performed to set an access sleeve in the milled out flapper valve utilizing an electro-mechanical setting tool. This access sleeve ensured that entry/re-entry through the milled flapper valve would be easily accomplished each time. The installation of the access sleeve was confirmed by running a 3.25 gauge through it. Milling of flapper valves and other well bore obstructions on electric line offers a cost efficient alternative technology to existing methods. Furthermore, it provides HSE benefits and logistical advantages by reducing the amount of required equipment and personnel.

Find the full paper at https://www.onepetro.org/


Novel approach to combat the b annulus pressure build-up challenge

In December 2014 a metal annular packer equipped with sealing elastomers, was installed and verified in an offshore platform well in Norway. The annular packer was installed to function as a barrier element against pressure buildup from shallow formations in the overburden with limited flow potential, containing liquid only (no gas). The packer was installed between the intermediate casing and the production casing.


Tractor-conveyed magnetic fishing in an extended-reach lateral completion

As operators in the Appalachia basin explore the Utica formation that underlies the previously-developed Marcellus shale, economic and environmental drivers have pushed drilling rigs to their limits in delivering wells that are both deeper and have longer lateral sections.
These extended-reach lateral wells, with total measured depths (TMD) exceeding 18,000 ft, impose new completions challenges stemming from technical limits and the utilization of new technologies. This paper will demonstrate the need to adapt while dealing with new constraints. Specifically, this paper will report on the successful use of e-line, a tractor, and a magnet to retrieve a fish from plug-and-perf operations in an extended-reach lateral.

One major challenge in performing a plug-and-perf completion on the extended-reach lateral in this case study was that the toe of the well extended further than could be cost-effectively cleaned out with a service rig or coiled tubing. Therefore, large-bore cast iron permanent frac plugs, which are designed to be produced through, were used to isolate frac stages in the toe. Before pumping a subsequent stage, a dissolvable ball was seated on the plug to isolate the previously fractured stages.

While plugging and perforating, the wireline adapter kit of the plug setting tool backed off the toolstring, creating a fish above the plug. It was unclear if the adapter kit was still whole or had broken into multiple components. The challenge in recovering the fish was that if it had disassembled, smaller components of the assembly could potentially slip through the bore of the recently set plug. If this occurred, the plug would need to be milled before a fishing attempt could be made.

Therefore, it was concluded that the fishing tools needed to be able to delicately engage the fish but still achieve a sufficient bite to hold the fish as it was dragged up the lateral. An overshot tool conveyed on coiled tubing was deemed too aggressive. Similarly, pumping down a wireline fishing tool was dismissed as the force from the pump down could potentially push the fish through the bore of the frac plug. Therefore, the decision was made to tractor-convey a rare earth magnet on e-line. This method successfully retrieved the fish on its first run, saving at least 3 days compared to the next-best recovery method.

This paper will detail the planning and execution of this fishing operation in order to provide insights for planning other extended-reach lateral completions. Specifically, this paper will show that existing technologies can be employed to overcome the challenges associated with fishing in extended-reach laterals.

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Increasing Operational Efficiency in Extended Reach, Offshore Wells – A Case Story from Middle East

A case story from ME will be presented covering an extreme extended reach, offshore well. Any increase to operating efficiency can save time and increase production. In this case story two SSD's were opened in a single run on e-line, an outstanding achievement due to the ID restrictions and extended reach of the well. The paper will discuss the planning, the operation, the achievements and the lessons learned.

This well was recently worked over, retrieval and new installation of upper and lower completion. Due to the well going on total losses during the workover, a closed system was deployed to enable the operator to set the hydraulic packers. The packer is utilized for isolation between two zones, with each zone having two SSD's in which one SSD per zone was required to be opened to allow access to the formation.

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Novel well flow-control valve for flexible well completion and application in commingled production of oil and gas in west Africa

This paper presents the development, qualification and field trial of a novel well flow valve that delivers unlimited zonal selectivity in single skin lower completion without the use of control lines. Control lines have limitations and risks due to complexity during deployment, restrictions on the number of zones, complications with liner hanger feed thru and associated wet connects.

It is desirable to remove the control lines whilst maintaining the functionality of multi zone, variable choke flow control. The well flow valve is a full-bore, reliable and robust mechanically operated sleeve, qualified in accordance with ISO14998 including multiple open/close cycles, at a sustained unloading pressure of 1,500 psi, with highly customizable flow ports.

The need for such a solution was identified by an operator in West Africa. The well objective was elevated from a gas producer to a well that required the flexibility to produce gas or oil with gas lift capability. The well flow valve was selected and required on site variable choke capability for both oil and gas production, with choke position verification, ability to handle dirty gas production without risk of plugging, compliant with a high rate and high pressure proppant frac along with ease of operation and long term reliability.

The field trial included a high pressure proppant frac in the oil zone. In the shallower gas zone, three well flow valves were used to deliver variable choking capability from maximum gas flow rate with minimal delta P adjusting down to a choke size suitable for gas lift. The well flow valves were operated using a high expansion shifting key conveyed on eline through the 3 ½” production tubing. The shifting key expanded in the 4 ½” lower completion to open/close individually all the well flow valves in a single trip. Incorporating this new product overcame the challenges presented and met the objective of commingled production of oil and gas. The well flow control valve demonstrated flexibility through design, supply chain, manufacturing, and operations. This paper will also outline the future road map covering further developments of the well flow valve and its incorporation into an enhanced flexible lower liner solution aimed at lowering well completion costs and risks.

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Annular barrier as an alternative to squeezes in challenging wells: technology review and case histories

The drilling industry has always relied on cement as a primary barrier. Although the cement represents about 5% of the well cost, when squeezes are required, cementing averages 17% of the well cost. Only 50% of the squeezes achieve the objective of establishing a barrier for well integrity.

A little bit more than half of the failures can be attributed to operational challenges (pump failure, cement contamination), or design oversights (cement recipe, centralizers). However there are still cement failures with perfect design and field execution. These failures typically exhibit some of the following characteristics: high deviation, high pressure, washouts, natural fractures, long casing section, heterogeneous sands.

For these specific conditions, it is beneficial to add an assurance that would maintain the integrity of the well even in case of bad cement. Some of the assurances used include port collars, external casing packers (ECP) and swell packers. Port collars allow a squeeze above the first stage cement, while ECP serves as a base for a second stage cement, and swell packers provides a baffle for sustained casing pressure. A more recent technology is the well annular barrier that can form a combined barrier with cement, and can also be used as a stand-alone primary barrier.

The well annular barrier is a metal-expandable barrier that is expanded with hydraulic pressure. It is full bore, highly customizable, and qualified to ISO 14310. The metallurgy allows the packer to shape fit into either an open hole with irregular geometry or inside a casing to preclude annular pressure build up by giving a life-of-well reliable seal. The well annular barrier has been deployed in a variety of wells to achieve well integrity with and without cement, protect the B-annulus from sustained casing pressure, or serve as a barrier between reservoirs that cannot be commingled.
This paper performs a review of the technologies used for cement assurance, their advantages and disadvantages. Case histories of well annular barrier deployments are presented, including a case where the well annular barrier was used as a stand-alone well barrier element without the need for dispensation. This paper also discusses how the well annular barrier fits into the regulatory requirements for well construction providing to the drilling industry an alternative to cement for the purpose of well integrity.

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A Case Study of the Successful Deployment of Tractor Conveyed Perforation in Highly Inclined Well

Well A is one of the only two wells on the XY reservoir structure providing the optimum drainage point on that reservoir. However, Well X had been shut in due to high sand production and had been flagged as ‘non-integral’ with regards to SPDC Well Integrity Management (WIM) policy due to its faulty Tubing Retrievable Surface Controlled Subsurface Safety Valve (TRSCSSSV). The well was thus scheduled for repairs.

The objective of the workover operation as with most others done in SPDC was to restore integrity of the well, remediate sand control and improve production across the XY reservoir.

On re-entry into the well, a mechanical restriction was met in the high angle section of the well thus impeding access to drain hole. A review of the situation, showed a possible collapse of the lower completions (sand screen) possibly due to high sand production. An attempt at sand clean-up was futile.

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Evolution of a Well Annular Barrier for Mitigation of SCP

A novel, Well Annular Barrier (WAB) was introduced back in 2011 as an open-hole, zonal isolation packer. Its strength, ruggedness and pressure capacity over the past four years has proven it a valuable solution. Especially for ensuring the successful cementing of casing strings which were required to be run through challenging environments such as overburden, depleted zones, water bearing sands or unconsolidated zones.

Work is in progress to develop a verification system for WAB expansion and integrity, further growing its capabilities and the operating envelope in which it can be deployed. This will in turn increase the WABs potential applications, and use as a stand-alone, open-hole barrier.

The newly developed system consists of pressure and temperature sensors either mounted independently from, or integrated with, the WAB. Annular sealing integrity will be confirmed by direct pressure measurement down-hole. 

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The World's First Gate Valve Milling on E-Line Returns Well to Production Faster and Safer

Stuck wellhead gate valve at surface offers and demand an extreme well integrity operation. Subsequently; well intervention operation needs more attention and might become more complex using conventional milling techniques. Conventional milling techniques have also fail to meet required well control or found to be lengthy and costly operation.

The world's first novel gate valve milling operation using e-line has been performed safely and successfully in Saudi Arabia. Saudi Aramco; land based oil producer well; located in Southern Area of the Ghawar field; was shut-in due to malfunction of Tubing Master Valve (TMV) on closed position for Signal Stack-Up X-Tree. 3,000 BOPD and well accessibility were locked with expected 1,600 psig as shut-in wellhead pressure underneath the stuck valve gate is the case.

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Enhanced Multilateral Reservoir Monitoring for the First Time in Offshore Abu Dhabi Utilising New Well Intervention Technology

Changing oil field development economics has pushed the trend towards developing multilateral wells to increase production and maximize oil recovery utilizing advanced well configurations. However, to focus on maximizing the value of multilateral wells by addressing reservoir and production challenges; efficient reservoir management has remained a challenge. Accessing multilaterals has not been possible with conventional Coiled Tubing logging techniques. Current available technologies for deploying Production Logging services in the multilaterals are of less success, due to hardware limitations.

The challenge was to access slim hole laterals from the mother bore in order to perform reservoir surveillance activities namely production logging as well as acidizing operations in laterals previously inaccessible.

The information gathered from this intervention would improve the overall understanding of the reservoir and well behavior thus enabling the operator to manage the multi-lateral wells’ individual drains, ensure production assurance and sustainability and revisit the development plan for the tight reservoirs based on proper reservoir evaluation.

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Technology Trial Review: Selective Coiled Tubing Re-Entry of Two Open Hole Multilateral Wells Using Intelligent Electromechanical Arm

A maximum reservoir contact (MRC) well, by definition, is a single or a multilateral horizontal well with more than five km of total contact with the reservoir rock. Planning of these wells requires extensive modeling studies to optimize total length, placement and configuration of branches.

The main objective behind the MRC well concept was to improve individual well productivity and hence reduce the unit development cost and to better develop hydrocarbon assets. In fact, oil fields developed using MRC wells shows significant improvements in those wells performance in terms of increased PI, lower drawdown, and significantly delaying water and gas conning.

A major challenge that faces production engineers in their daily operations is identifying and accessing laterals windows in those MRC multilateral wells, in order to preform rigless downhole sensing and intervention jobs (logging, stimulation, etc.). 

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Technology Trial Review: Selective Coiled Tubing Re-Entry of Seven-Lateral Openhole Well Using Electromechanical Arm

The number of MRC (Maximum Reservoir Contact) wells has increased significantly since they were first introduced in 2002. Most of these wells use multilateral well configuration to increase the contact with the reservoir and therefore the well productivity.

One of the main challenges for multilateral wells is the selective accessibility of the well during the production phase to perform various rig-less activities (such as stimulation, production logging, water shut-off… etc.). This requires detection and confirmation of lateral window depth and orientation and means to allow the tool to be selectively steered into the desired lateral.

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Case History - Metal Expandable Annular Barrier for Zonal Isolation in Challenging Cement Operation in West Africa

It is well recognized that a failed isolation can have detrimental consequences on HSE, well productivity, and life of the well. This paper presents the case history of a metal expandable annular barrier used to provide cement assurance via a hydraulic seal in a challenging side-tracked well in West Africa. The initial well was shut in shortly after being brought on production due to excessive precipitation of scale.

Investigations identified a shallow formation separated from the production zone by a thin shale section, and prompted questions on the effectiveness of the cement across the production casing. The metal expandable barrier was then selected to assure sealing in the side-tracked well. Two barriers were mounted on the 9-5/8" casing and deployed through the milled window.

Following the cement operation, hydraulic pressure was applied to expand rapidly the sleeve bodies in wet cement and set against the 12 ¼" borehole thereby creating an impenetrable seal. The sealing was ultimately confirmed by the absence of scale during production compared to the previous experience of shut-in after only 18 hours of production.

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Advancement in Mechanical Manipulation Enables Pulling Forces of 60,000 lbs on E-line – Operational Experiences from Pulling Stuck Plugs and Tools

Accidental plug setting and stuck tools is a cause of great frustration, operational delays and ultimately deferred production. A cost-efficient and swift resolution is always desired. This paper presents a new development in engineering in the form of a hydraulic stroking tool with the ability to apply 60,000 lbs of force. The tool has already been applied in the North Sea; lessons learned from these recent operations are disclosed in this paper.

In one operation, a plug was accidentally set across the Christmas-Tree (XMT) and blowout preventer (BOP), effectively eliminating the XMT as a well barrier element and constituting a serious HSE risk. Conventional solutions failed to release the plug due to an insufficient pull force and then a failing jar.

In another well, the setting tool had malfunctioned, resulting in a partially set plug and a stuck tool. Repeated attempts with heavy duty fishing equipment had damaged the fishing neck, further complicating the fishing operation as the setting tool had failed before it could break the stud connecting to the plug.

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Combined Distributed Temperature and Acoustic Sensing with Production Logging for Improved Horizontal Well Evaluations

Distributed fiber optic (DFO) sensing makes it possible to monitor data, gathered over time, along the entire length of awellbore. Distributed Temperature Sensing (DTS) using a permanently installed fiber optic cablehas been a downhole permanent monitoring application for nearly 20 years. Fiber optic deployed intervention systems have been used with slick line and coiled tubing since 2008 and 2009 respectively which allows for real time downhole data monitoringduring interventions, previously unavailable with these conveyance methods.

Recently, another advancement in the intervention domain has been achieved with the development of a .36” diameter, electric wireline cable which includes fiber optics for both DTS and Distributed Acoustic Sensing (DAS), combined with production logging (PLT) measurements run in a “dip-in” mode. Temperatures and acoustics are recorded along the optical sensor cable, as a continuous profile while the PLT data is acquired in the traditional fashion. A primary industry benefit from this technology is in horizontal well applications where more robust measurements and analysis of production logging data is needed to quantify production profilesin multi-phase environments.

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Thinking Beyond the Conventional - A Case Story of Using a Surface Read out Wireline Device while Ranging to Reduce Risk of Failure During Drilling of a Sagd Well in Hot Zone

In the SAGD industry, it has become more common for operators to drill into active or pre-heated oil- sands zones. These hot zones provide for a challenging environment to drill a single well, let alone use electronics for active ranging technology for accurate wellbore placement.

This paper will discuss the intent of a new head tension-compression device and the process leading from extending conventional thinking into using it as a solution for a challenging wellbore environment. Through a case story, the challenges proposed by a client in Western Canada will be examined, as will the lessons learned from the unconventional solution.

When drilling SAGD well pairs, it is common practice to have an active ranging device placed in the “target” wellbore to aid in accurate well placement. The active ranging devices are electronic in nature and are limited to temperature exposure for reliable performance.

Collaborating with the operator, a secondary measurement provided by an e-line device was used in conjunction with field proven magnetic ranging equipment in order to provide real-time feedback to surface with the purpose of mitigating risks due to the high temperatures. The diagnostic device was used to monitor the effects of pumping fluid into the wellbore in order to cool sufficiently and thus protect the sensitive electronics in the active ranging device.

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Development and Field Trial of the Well-Lateral-Intervention Tool

Wells with extended-reach multilaterals have improved reservoir contact and have opened the opportunity for well-placement and -drilling optimization. Since the early 2000s, the number of maximum-reservoir-contact wells has increased substantially, and the benefit of these wells is being realized at the early implementation stage.

To enhance the performance of these multilateral wells, intervention operations in the laterals are required. Stimulation, data acquisition, and other operations are required to optimize the production from the laterals; however, accessing the lateral of any wellbore for intervention in a reliable manner is still a challenge.

The present paper describes the development of an intelligent, real-time controllable tool, the well-lateral-intervention tool (WLIT), that can identify a lateral junction and steer an intervention/surveillance string into it.

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Use of Sliding Sleeve Valves in Long Laterals for Control of Production, Injection and Stimulation

Though extended reach completion has become more common in Abu Dhabi and the region, there are still challenges to overcome in completing of the lower completion in order to have better control on production, injection and stimulation, especially, when the reservoir characteristics vary along the lateral.

Multiple horizontal wells with different lower completion design have been drilled and completed in the region, e.g. Pre-Perforated Liner (PPL), Limited Entry Liner (LEL), Inflow Control Device (ICD's) & Inflow Control Valve's (ICVs). All of these laterals have been designed to have multiple compartments with certain separation in order to control the stimulation job either by bullheading (pumping from surface) and/or using coiled tubing (acid wash).

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New Electronics Ensure Increased Operational Efficiency in Highly Deviated, High Temperature Gas Well

This paper describes a case story from Saudi Arabia where an extreme downhole environment required new developments in electric line intervention technology. This operation was the first time the new DC electronics package was used in the Middle East.

A major operator needed to test casing integrity and perform a perforation on a high pressure/high temperature well (310°F, 91° horizontal well). Standard wireline conveyance was not an option, pump down logging wasn’t available, and coiled tubing was too time consuming. New technology had to be considered. Multiple feasibility studies, including heat studies, were performed to verify that an e-line tractor equipped with newly developed DC electronics equipment would be able to execute the job under the extreme well conditions.

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A Practical Method of Predicting Calcium Carbonate Scale Formation in Well Completions

Scale formation in downhole tubular‐flow passages can cause partial to complete plugging that will affect production or injection rates adversely. In an intelligent‐well completion in which the interval‐control‐valve (ICV) opening must be changed to control flow rate, the completion will become ineffective if plugging of clearances prevents valve actuation. To mitigate these problems, a method to predict the potential rate of scale formation under realistic conditions has been developed.

This empirical method allows prediction of tool performance under scale‐forming conditions for downhole applications, and uses chemical data and flow fields generated by computational‐fluid‐dynamics (CFD) models for downhole tools. Chemical data are obtained from laboratory tests on coupons by use of brines matching the chemistry of connate fluids.

Tests were conducted in a high‐pressure, corrosion‐resistant vessel over a range of high pressures (100 to 10,000 psi) and high temperatures (75 to 150 °C) to simulate downhole well conditions.

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Challenging Well Completion and Intervention Technique for Multizone Offshore Brown Field Well

XX-1 is a newly drilled well in Ravva field in eastern coast of India deviated to 70 deg and completed with a 6? Open-hole section. The initial completion plan for the sand prone well was to complete with stand alone screens for a single pay zone. During drilling, additional pay zones were encountered which necessitated completing the well with zonal selectivity using sand-screens with SSD. Selective completion required thru tubing intervention to operate the SSDs and produce selectively.

Due to high deviation, intervening with slick line was very challenging whereas coiled tubing operations had its own limitations which are discussed in the paper. Hence it was decided to use Electro-hydraulic stroking tool along with motorable tool sections to convey tools in the high angle well.

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Technology Update: Flexible, Single-Skin Completion Concept Meets Well Integrity, Zonal Isolation Needs

As deeper and more complex well designs proliferate throughout oil and gas fields, well completion methods are challenged and new technologies are emerging to ensure safe, cost-efficient, and optimized completions.

The Welltec Flex-Well completion concept is a flexible, single-skin (monobore) system that allows fit-for-purpose completion designs that can be as minimal or intricate as needed for optimal reservoir drainage and do not require the use of cement or swellable packers

Reliable and effective annular barriers continue to be crucial to well management for safety and performance. Cementing has been the industry’s conventional means of creating these barriers, having been used for almost 100 years (American Oil & Gas Historical Society 2015). However, the industry is not drilling and completing wells the way that it did a century ago.

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Well tractors for highly deviated and horizontal wells

This paper introduces the oil industry to a new type of downhole tools – the Well Tractors with modular power source designed for running in open hole and inside the completions of horizontal and highly deviated wells. The Well Tractors are used for cleaning, setting and pulling of plugs, operating sliding sleeves, open hole logging, running of production logs, drilling, perforation guns, cement bond logs etc.

Horizontally the Well Tractors pull coiled tubing and/or wireline beyond 10,000 ft. The Well Tractors are capable of pulling more then 25,000 ft of coiled tubing and/or wireline into a highly deviated well. Furthermore the tools are designed for pushing other tools into the hole, e.g. logging tools, video cameras etc.

The Well Tractors with modular power source are designed in two versions:
A fluid driven version for coiled tubing operations. Powered by brine, water, mud etc. which is pumped down through standard coiled tubing. The tool is controlled from the surface via a wireline running inside the tubing. Through the wireline measurements can be transmitted to the surface. Alternatively the tool can also operate without the wireline which enables it to run with a smaller size of coiled tubing or have a higher flow rate for e.g. cleaning jobs.

An electric driven version of the Well Tractor for wireline operations. Powered and controlled through the wireline.

The Well Tractors are designed in 3 different sizes. A Tractor with an outside diameter of 3 1/8″. A Tractor with an outside diameter of 4 3/4″ and a Tractor with an outside diameter of 2 1/8″.

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The application of new wireline well technology to horizontal well logging and intervention: a review of field experience in the north sea

Through close co-operation between Statoil MWS and Welltec, a working Well Tractor has been successfully introduced into operation in the North Sea.

The Well Tractor technology has been extensively field proven and has demonstrated significant cost savings for operating companies when compared to previous methods of performing well intervention operations in horizontal wells. In some cases, use of the Well Tractor technology can mean the difference between whether or not required well intervention operations can be carried out.

Careful pre-job planning is necessary to ensure success, since the Well Tractor technology adds a new dimension to the techniques required in normal wireline logging and well intervention.

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New applications for 2 1/8" well tractor inside 5" drill pipe

This paper describes the use of Well Tractor? technology to convey services for recovery of stuck drill pipe in circumstances where conventional methods were considered economically or technically unfeasible.

In the first case, the drill pipe became stuck while running in and circulation was subsequently lost. After 100 jarring cycles were performed it was decided to attempt a fishing operation using the 2 1/8” Well Tractor enabling the retrieval of the radioactive logging source. The retrieval tool was deployed on Well Tractor, which enabled the radioactive source to be successfully recovered from the bottom hole assembly (BHA). The drill pipe was subsequently backed-off using Well Tractor to convey the explosives.

In the second case, drilling losses to the formation were experienced and it was decided to pump lost circulation material. However, during pumping the drill pipe plugged up completely. At the same time flow was recorded on the annulus side and the drilling BOP annular preventer was closed with subsequent pressure build-up below. A 2 1/8” Well Tractor was successfully run inside the DP to first gauge and subsequently punch holes in the drill pipe to open for circulation, thereby allowing pumping of heavy mud and regaining well control.

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World's first successfull openhole logging job with the well tractor enables faster and cheaper field developments

An openhole logging job was carried out in December 1999 using a Welltec Well Tractor in a 3.8 km long, horizontal, water injector in the Lekhwair field in Oman.

Two logging runs were carried out by Schlumberger, one of which reached the world record distance of 1550 m in openhole (3012m along hole). Water flow log (WFL) and full bore spinner (FBS) data were measured and confirmed that injectivity is uniform along the length of this well, providing confidence in the current line drive, water-flood field development. This is the first time that quantitative logging data has been obtained from an openhole using the Well Tractor.

This data, coupled with recent production data from other long wells in Lekhwair, provided the confidence to propose and drill extremely long horizontal wells (up to ~4 km openhole length) in 2000, resulting in a significantly more cost effective and faster field development.

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SPE 123924

Milling of Permanent Bridge Plug Successfully Performed on Wireline

A technological breakthrough within the application of wireline technology has been achieved. In August 2008, on an offshore platform in the Norwegian Continental Shelf, a wireline tractor and a new wireline milling system were used to mill and remove a permanent bridge plug at 4,147 ft MD.

The operator decided to mill out the plug on electric wireline and worked closely with the service company to develop this novel solution. Having developed and tested several bits and milling tools, results showed that by combining the wireline miller with hydraulically provided weight on bit (WOB), it would be possible to mill out the retaining rings of the plug, which would cause the plug to collapse. The milling control unit allows the WOB to be adjusted for each application and also controls the reactive torque, the force generated when the milling bit engages the plug.

The service company was able to develop the solution within the client's parameters and in accordance with the timeline set out for this project. The offshore operation was completed in three days to the operator's satisfaction.

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SPE 68409

Performing tractor perforating operations from a vessel in 1,120 ft water depth offshore Norway

The paper will describe Statoil’s motivation for selecting a light well intervention vessel rather than a semi-submersible drilling unit for perforating two subsea wells offshore Norway during September 2000.

The paper will further discuss the challenges and the experiences captured and gained from the operation. The water depth was world breaking for this type of well intervention vessel operation, with a water depth of 341 m (1120 ft).

Another world’s first from a vessel, was the deployment of a wireline driven Well Tractor® to convey lowside orientated perforating guns out in the deviated wells, incorporating the shortest tractor length ever deployed. The wells were water injectors, slightly under balanced and treated as live as hydrocarbons could enter the wells after the perforating. The longest well was 5657 m MD (18560 ft) and with highly deviated step out of approximately 2973 m MD (9754 ft). The paper will conclude with lesson learned and cost benefit issues.

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SPE 68887

New coiled tubing well tractor extends lateral reach

Smaller OD Coiled Tubings have been known to buckle and, in extreme cases, lock up, thus having a limited lateral reach capability for most directional well intervention and drilling operations.

The application of the Well Tractor facilitates the use of Coiled Tubing on offshore platforms where it previously could not been utilized due to crane and/or platform deck loading limitations.

This paper describes the innovative Well Tractor tool developed to extend the envelope for CT operations. The tractor is fluid driven and capable of over 2500 lbs pull/push. It is designed to work with acidifying fluids, nitrogen or drilling muds.

Also covered are the working principles of the CT Tractor and comparative calculations of lateral CT reach with and without the tractor. In addition, a world record setting CT tractor case history is discussed.

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SPE 89522

Zonal isolation in a u-shaped well using coiled tubing and well tractor

An 80 m long retrievable “one-run” straddle assembly was successfully installed in order to shut off a gas breakthrough in the 130° deviated reservoir section of a “U shape/Fish hook” sub sea oil producer in the Njord field. Coiled tubing with an internal electric line in combination with a tandem fluid driven tractor was used to convey the straddle assembly.


Njord is a sub sea completed oil field operated by Hydro, located offshore northwest Norway. Njord "A" is a floating drilling and production unit. The well is an oil-producer in the Tilje formation, completed with a 7-in" production tubing and a 7-in" perforated liner (Fig 1&2).

The objective was to isolate selected intervals in the reservoir section at 130 degrees inclination in the "toe" of the well in order to reduce the gas to oil ratio (GOR). The chosen method was to install a purpose designed straddle packer assembly utilizing coiled tubing and tractor.

Job Design

Based on computer simulations, it soon became clear that it would not be possible to reach the desired depth using coiled tubing and conventional "extended reach" techniques alone.

Computer simulations using reduced friction coefficients and/or altered fluid densities only improved results marginally and indicated that the 2-in" (optimized taper) coiled tubing at best would go into a lockup 174 meters away from target depth. Computer simulations using 2-3/8-in" coiled tubing also showed similar results with a little added penetration. CoilCAT* software was used for modeling of tubing forces in the well.

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SPE 90385

A novel technique to acidize horizontal wells with extended reach

Drilling horizontal wells with extended reach is intended.to maximize reservoir drainage and minimize water production due to water coning. However, an inherent problem with these wells is poor acid distribution during matrix acidizing, especially in reservoirs with high permeability streaks.

This paper discusses an innovative approach to treat horizontal wells with extended reach. This new technique comprises mechanical diversion in the wellbore, and chemical diversion in carbonate formations.

Coiled tubing has been used for years to better distribute the acid in vertical and horizontal wells. However, application of coiled tubing in long horizontal wells is a function of wellbore diameter and length. Coiled tubing cannot reach the total depth of the well if there is large washout, or if the length of the open hole is greater than what the CT can reach. The maximum length that CT can reach depends on the length of the reel, diameter of the coil and wellbore geometry. To extend this length, we have used a hydraulic tractor to pull the coiled tubing to the total depth of the well. This will ensure better acid distribution over the wellbore. To enhance acid diversion in the formation, a visco-elastic surfactant-based acid system was employed.

Wells selected are horizontals that were drilled in a carbonate reservoir in the oil fields (both land and offshore) that are present in the eastern part of Saudi Arabia. The total length of the target zone for the Well “A” and Well “B” is 13,543 and 20,304 ft, respectively. Typical coiled tubing (1 ¾-inch) cannot reach the total depth in these well (CT lockup length is 10,300 ft for well “A” and 13,320 ft for well “B”).

A special hydraulic tractor was used to pull the coiled tubing to the total depth of these two wells. A visco-elastic surfactant based acid system was utilized to remove formation damage induced by the drilling fluid (water-based mud) and enhance the permeability of the formation in the critical wellbore area. Corrosion inhibitor and other acid additives were carefully selected to maintain the integrity of the well tubulars, coiled tubing and the tractor (metallic parts, O-rings and seals of the tractor). Before attempting the stimulation of the extended reach well, a water jetting method was adopted to remove near well bore damage resulting from the drilling mud cake and mud invasion. Production logging tests were conducted after drilling the well, after the water jetting treatment, and after the matrix stimulation. The productivity index of the well decreased after the water jetting treatment. However, the acid matrix treatment delivered through the CT tractor nearly doubled the productivity index of the treated well.

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SPE 96093

Case history: designing and implementing wireline tractoring applications for deep water, extended-reach, sand-control completions, and interventions

Wireline tractoring technology has set world and Gulf of Mexico records for several logging applications during the initial completion and intervention of two extended-reach, deep water frac pack wells and one extended-reach, deep water water-injection well.

This paper reviews some of the challenges involved with conventional conveyance methods in extended-reach wells, describes the planning process for wireline tractoring operations, including prejob modeling, and summarizes the results of a project. The authors will also share the lessons learned and best practices implemented. Proper utilization of this technology has led to significant cost savings for the example project.


The Petronius project, located 150 mi south of Mobile, Alabama in the Gulf of Mexico, is operated by Chevron Corporation, with Chevron Corporation and Marathon Oil Corporation having a 50% working interest in the project.The project was sanctioned in August 1996 after a compliant tower and subsea development options were evaluated.The compliant tower alternative was selected based on superior well intervention capability, less complex seawater injection system designs, lower investment, and future hub potential.The 2,001-ft tall Petronius compliant tower is set in 1,754 ft of water, and is the world's tallest free-standing structure.

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SPE 19182

Isolation valve contingencies using wireline stroker and tractor technologies

Many subsea completions employ a down hole isolation valve for temporarily closing off production while awaiting first oil or flow line connections. These valves are designed to be opened or closed through surface pressure pulses in the fluid column to activate stored nitrogen in the valve housing.

When a valve fails to activate as expected, a reliable contingency plan must be ready or the financial consequences can be large.

With the use of electric wireline tractor technology, a contingency valve opening system allows malfunctioning isolation valves to be mechanically shifted with depth precision and controlled force. This method uses an electrically powered hydraulic stroking tool to shift the valve sleeve open or closed with a selected force of 10 K – 30 K lbs depending on the type of valve. The stroking tool is either tractor conveyed in high angles or run with only a shifting tool attached in low angles. A new intelligent key tool replaces the spring loaded shifter, to allow the system to be run “slick” and avoid hang ups on down hole profiles that can occur with the conventional spring loaded shifting tools.

An electric line deployed solution is faster to mobilize, more precise in locating shifting sleeves and less expensive than alternative solutions. A review of case histories will prove these points. Also, pre-job planning, integrated team involvement, SIT and operational recommendations will be discussed.

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Downhole water management and robotic valve manipulation on electric wireline

Due to high operating cost and challenging environments, the oil and gas industry is facing an increasing demand to identify areas where new intervention solutions can be applied. Downhole water management and robotic valve manipulation are some of the areas where new approaches are finding critical success.

A new technology has enabled increased recovery rates by managing produced water and allowing remote mechanical manipulation of downhole valves on Wireline. These services are possible when applying a robotic stroking device and a Wireline key tool combined with field proven Wireline Tractor technology – best described as Well Construction on Wireline in a highly deviated well.

This technology represents a cost-efficient method for setting and retrieval of specific downhole hardware (i.e. plugs and straddles) as a resource-efficient alternative to existing technologies.

This paper will present case histories and the benefits of operation, particularly in deviated wells, where tractor technology in combination with the Wireline Stroker exemplify the advantages of the subject technology.

In a well offshore Norway, producing since 1995, completed with 2 Sliding Side Doors (SSD) to control zone production, attempts had been made to close both SSD’s in October 2003, but only the upper SSD was possible to close. A two-piece straddle was sat above the lower SSD, which however showed no change in production. PLT results showed an internal leakage in straddle and tubing; straddle was therefore retrieved in February 2006 and the well temporarily plugged.

Later in 2006, it was decided to perform a new intervention in order to remedy the situation and a Tractor/Stroker combination was considered optimal for performing the operation, as an alternative to a Coiled Tubing operation.

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SPE 143226

Riserless well intervention for subsea workover

The number of subsea wells has increased steadily over the years and is estimated to have exceeded 5500 by the end of 2010. Subsea wells do in general have substantially lower recovery rates than what is normally achieved from comparable non-subsea wells.

This is due to the high intervention costs which are directly related to the rates of the rigs required to carry out such operations if the traditional and conventional approach is adopted. Hence the incentive to increase recovery rates has been limited as the balance between cost and revenue has been unfavorable, even with increasing oil and gas prices. However, this has also stimulated the development of alternative methods which can enhance recovery rates and not least address the challenges created by more fields passing maturity and exploration moving to more demanding areas.

Lightweight and riser-less intervention well intervention has in this context become a proven approach with considerable potential for driving the future development. The ability to substitute large rigs with smaller and dynamically positioned light well intervention vessels has a major impact on cost and time. Riserless intervention as such has been done regularly for a number of years and has set excellent HSE standards. However, in recent years the use of riserless well intervention has become increasingly instrumental in the effort to enhance recovery rates and general performance.

The paper gives an account of a scale milling operation carried out at a Norwegian field in the North Sea where two wells both suffered from a significant drop in production.

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SPE 147674

Practical aspects of in-situ ball seat milling

A ball seat placed deeply in one of the wells in the North Continental Shelf (NCS) had to be removed as part of a reconfiguration work-over. To achieve this, a milling operation scheme was devised. As this was the first time a ball seat of this type had to be removed by milling in the NCS the operation was rehearsed and evaluated onshore.

An identical setup with two sizes of seats and balls was established in an almost horizontal pipe setup onshore and the tool-string consisting of a conveyance tractor mounted with a milling device fitted with a tungsten carbide bit was driven into the pipe. The milling was carried out with different levels of weight on bit by adding back-tension on the cable as well as using different numbers of drive sections on the tractor. Then the results were evaluated. Additional tests were carried out with parts of a milled ball dropped down hole on the ball seat to ensure that milling could be done. The tests showed that the tool-string as configured could mill out the ball seats in one operation. This was later confirmed as the actual seat situated at 12.647 ft. measured depth was removed in one run.

The paper provides a detailed account of the preparations and actual milling operation, including the lessons learned and how the objectives were achieved.

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SPE 146017

Modelling of cable forces as a decision support tool for RLWI operations

Subsea well intervention has been performed extensively over at least two decades to service wells and to increase recovery from these wells.

It is a well known fact that subsea wells normally under perform platform wells in recovery between 15-20%. To a large extent, the gap in recovery is related to the high cost in access to the subsea well compared with surface or platform wells.
Efficient and low cost well intervention techniques are of the out-most importance for increased field recovery. Riserless Light Well Intervention (RLWI) is one of the tools helping to close the recovery gap.

RLWI operations are now common in shallow water depth up to 600 meter although at least one operation has been performed on 906 meter water depth.

Considerable efforts have been made to improve the RLWI system with respect to efficiency, weather sensitivity and at last – but not least – deep water compatibility.

During RLWI in deeper water, the environmental loading on the wireline from the vessel to the subsea equipment becomes the limiting factor as the wire is subjected to considerable loading from sea current.

Welltec, one of the pioneers in RLWI operation have started an R\&D program to fully understand the limitations and to provide the operator with a tool to assess if RLWI is possible based on simulated behavior and empirical data instead of merely stating that RLWI is not possible beyond a certain water depth.

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SPE 147082

A novel well annular barrier solution alternative to swellable casing packers

Having safe effective annular barriers that can be used for annular isolation is the key for managing wells. This has traditionally been done by either cementing the annulus or through the use of swellable packers.

The use of cement as annular isolation usually is considered as the industry standard, however it is a complicated, time-consuming and expensive to deploy. Alternatives, such as polymer-based swellable packers, are usually less complicated to deploy, but the degradable polymers invoke a risk in the typically harsh environment of a well.

The approach presented is based on a solid metal expandable system developed for the applications where swellable external casing packers traditionally have been used. The well annular barrier provides long term robust and reliable zonal isolation in cemented or un-cemented wellbores and may be used in conjunction with casing as well as liners. It also provides higher differential pressure capacity and higher expansion ratio to running OD without compromising the inner diameter. Consequently it does not impair or restrict flow conditions and furthermore enables subsequent well maintenance to take place unhindered.

The paper presents the results of the development and testing of the new solid metal expandable system for external casing applications and discuss the rationality behind the technology as well as the experience gained.

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SPE 143358

Light well intervention scale milling enables reservoir access

This paper will present a record North Sea electric line milling operation carried out during March 2010, the success of which enabled access to the reservoir section, with subsequent interventions leading to a significant uplift in production.

The Operator was experiencing high water cut in one of its wells; previous interventions in other wells connected to the same reservoir indicated a high probability of scale. The plan was to log, isolate the watered out zone and then re-perforate in order to increase oil production rate. Electric line Tractor Milling equipment was mobilized as contingency, should well access be an issue, which happened to be the case.

In order to keep the bit clear during milling, cuttings were flowed back to surface. Progress was made until the surface choke packed off and flow was no longer achievable, the toolstring had to be retrieved whilst choke and lines were cleared. The scale sheath was eventually broached and the decision made to continue in hole in order to drift, as well as providing the capability of dealing with any further scale that may be present; the Tractor Miller was started once more with a minimum of resistance encountered. Target depth was attained, all Tools were then retrieved to surface with no issues.

The overall objective was achieved, resulting in a significant increase in production. One hundred and twenty one (121m, 390 ft) of calcium carbonate scale was removed during the operation, validating the use of light well intervention techniques when removing scale.

This paper will discuss the technical aspects of e-line milling and challenges overcome during this particular operation.

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SPE 154417

High-angle gas lift valve removal and replacement in a single run

An operator in Prudhoe Bay, Alaska required the ability to replace gas lift valves in their completion for improved oil production. Conventional methods had reached their limits due to extended well lengths and high-angle well deviations.

Slickline was unable to overcome the higher deviations, while imprecise depth control during coiled tubing operations required multiple run-in-hole attempts to pull and replace the valve.

Based on previous, positive experiences with electric line – mechanical solutions, the customer chose a unique solution using a newly modified Kick-Over Tool (KOT). Two KOTs run in tandem and combined with a tractor and a hydraulic stroking tool (HST) were used to pull the existing gas lift valve (GLV) and replace it in a single run. The tractor conveyed the tool string to the correct depth where the HST and the first KOT provided the pulling force for removal. Then, the HST and second KOT were used to successfully install the new GLV into the mandrel.

The operator is now able to optimize their gas lift design without the limitations imposed by conventional means for installing GLVs such as slickline and coiled tubing. This allows them to place gas lift valves in the high angle sections when necessary for increased oil recovery from their reservoirs.

Few changes have been made to the Kick-Over Tool technology in the past 40 years but it has been recently improved to operate more reliably in deviated and horizontal wells and has been modified to accommodate the forces generated by the HST. This paper will describe the challenges with the planning and execution of this operation and the implications for future gas lift design.

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SPE 154411

Case story: rigless debris removal from a subsea safety valve with a wishbone honer brush on electric line

Subsea safety valves (SSSV) are safety-critical when a well has sufficient reservoir pressure to flow naturally. Among other things, they are used to secure offshore wells during hurricanes to prevent pollution in the unlikely event the wellhead sustains damage. They are tested regularly and must be reliable.

While testing a SSSV in one of its wells in the Campeche Bay, a major Latin American Operator discovered scale deposits that prevented the SSSV from sealing shut. The operator was looking for an alternative mechanical solution, since pumping acid into its wells had not been effective. A downhole tractor service provider approached the operator and after carefully studying the case, presented the wishbone honer brush design run on a well tractor and electric line to repair the valve in situ and avoid costs associated with mobilizing a rig and removing well components. It was the first time this technology was used successfully for this application.

The operator deployed the cleaning equipment in August 2011 and performed the work in 18 hours operating time. The SSSV tested successfully on the following day and the well was returned to production. The operator estimated that the selected technology saved more than a week of deferred production at 7500 BOPD and direct costs of rig mobilization. The wishbone honer brush tool run on a well tractor and electric line proved to be the alternate solution they were seeking and it is now the operator’s preferred technology for this application.

This paper will present the operational challenges as well as the results of this successful, rigless cleaning operation on an important producing well.

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SPE 154405

Milling of an electric-line obstruction with electric line conveyed technology

A new application of electric wireline tractors in combination with the well milling technology has been successfully proven in an offshore Equatorial Guinea well.

In July 2011 on a small, unmanned offshore platform in Equatorial Guinea, a downhole tractor and a milling tool were conveyed on electric line to remove an obstruction created by Lost in Hole (LIH) electric line cable and production logging tools (PLT).

By using customized core milling bits, 13 successful milling runs were made. During this unique operation, most of the milled wireline material was recovered, and the challenges of controlling torque and milling penetration were achieved. In between milling runs, slickline fishing attempts were made in order to recover the remaining LIH wireline. After the last milling run, a major breakthrough was made when the PLT string moved downhole to a position that uncovered the proposed new completion interval. Ultimately the well was perforated and returned to production at projected gas and condensate rates.

Milling of wireline and other well bore obstructions on electric line offers a cost efficient alternative technology to existing methods. Furthermore, it offers reduced Health, Environment and Safety (HES) risk benefits and logistical advantages.

This paper will describe the actual process from preparation to completion of this first-of-its-kind fishing operation.

Find the full paper at https://www.onepetro.org/

SPE 159636

World's first riserless light well intervention (rlwi) technique to mill and clean hard-packed debris, and then pull a bridge plug form a live subsea well using electric wireline

A subsea production well in the North Sea was being serviced with a riserless intervention which inadvertently resulted in fill atop a temporary bridge plug. Riserless slickline and traditional e-line attempts to remove the debris and pull the plug were unsuccessful.

A rig or intervention vessel with riser for coiled tubing cleanout was unavailable for approximately a year. The operator requested innovative solutions and selected a unique riserless light well intervention consisting of an e-line cleaning tool with a reverse circulating bit and bailer sections to break through the hard-packed debris, vacuum it into the bailers, and retrieve it to surface.

The remaining debris in the internal fishing neck of the plug was sucked up by a high-powered e-line cleaning tool and the plug was pulled in the same run. The job was executed without incident from a small, dynamically positioned, vessel with a moon pool and a subsea lubricator, saving the operator about one year’s deferred production versus waiting for the coiled tubing solution. This paper discusses the operation of the downhole tools and procedure for riserless deployment to achieve the objectives and create this value.

Find the full paper at https://www.onepetro.org/

SPE 159852

Successful application of electric line tractor assisted logging and perforating technology saved significant time and associated rig costs, and set two new regional records in Latin America: a case study

A new well logging/perforating challenge arose from a Highly Slanted (HS) exploratory well that was drilled in Colombia. This HS, exploration well (up to 75 degrees inclination) was drilled in the “Llanos Area” to 18,040 ft MD.

Available logging and perforating technologies were reviewed and evaluated which included Drill Pipe, Coiled Tubing and e-line options. Tubing Conveyed Perforating (TCP), using a combination of Drill Pipe (DP) / tubing string and Coiled Tubing (CT) perforating technologies was considered as part of the evaluation, but the selected method was an e-line well tractor to deploy the logging tool and perforating assembly. Using tractor conveyance saved significant time and associated rig costs with respect to pipe conveyance to perforate this new well. In so doing it also set two, Latin American, regional records for tractor-conveyed tools in one well.

Based on site-specific experience, the operator concluded that each well intervention with drill pipe would require 48 hours per trip. In August 2011, after a formal risk analysis and systems integration testing (SIT), the operator mobilized a down-hole, robotics-solutions provider and successfully tractored a cement evaluation log to 11,079 ft. A regional record was set for longest tractor-conveyance during the first perforating run of 12,095 ft. A second perforating run of 11,037 ft was successful and set a regional record for longest, cumulative, tractor-conveyed distance in a single well at 34,211 ft. The cement evaluation and perforating runs were completed in less than 40 hours versus more than 96 hours, which was the estimate with pipe conveyance. The results of operations in the HS Llanos well are presented. Lessons learnt from these operations are part of this study.

Find the full paper at https://www.onepetro.org/

SPE 111818

Optimized Well Performance With Electric Line Interventions

In recent years, re-invention and development of electrical wireline mechanical applications, initially for high-angle well-access in conjunction with wireline tractors, has proven able to unlock value potentials by allowing interventions, previously thought impossible or cost prohibitive, even in low angle wells. Common denominators are remote-control, rig-less operations and documented large value-creations.

This paper will present innovative areas of recovering production through various case histories.

Find the full paper at https://www.onepetro.org/


World’s First: Annular Barrier Installed in a Subsea, Deepwater Well without the Use of Cement

It is widely recognized throughout the industry that as wells get deeper and well trajectories get more complex, the challenge to establish effective cement for zonal isolation (ZI) increases.

This paper will present the results of the world’s first installation of a cementless liner using state-of-the-art well annular barrier technology within a subsea, deepwater, pre-salt well in Brazil. This new method demonstrates that maintaining an open sand face delivers lower skin and potentially higher productivity.

Find the full paper at https://www.onepetro.org/


Pushing The Limit Of Tractor-Deployed Wireline Operations On Al Khalij Field In Qatar

Over the past 2 years, a number of tractor-deployed wireline operations have been performed by Total EP Qatar on Al Khalij field, ranging from Corrosion evaluation, ballistic operations to Production Logging operations in various casing sizes and environments.

The paper presents the various applications of this technique on Al Khalij field.

It also demonstrates that the candidate wells feature horizontal sections that are amongst the most ambitious for the application of the wireline tractor technique.

Find the full paper at https://www.onepetro.org/

SPE 162720-PP

Recent achievements with electric line milling

Since the concept of milling obstructions on electric line (e-line) was introduced in 2005, operators around the world have applied this technique successfully removing downhole valves, plugs, scales, cement and nipple profiles achieving cost-effective and time-efficient interventions.

Recently, a series of e-line milling operations were performed to remove repeater-sub and ball-seat restrictions in oil producing horizontal wellbores located in Southeast Saskatchewan. The low pressure reservoirs favored intervention technologies that did not require excessive hydrostatic head. Operators have traditionally used nitrogen mixed with water to prevent damage to the reservoir and to maintain circulation; however, this reduces the amount of torque that can be achieved at the bit, and causes stalling and sticking issues.

Using a combination of tractor and milling technology on e-line in these wells provided the required torque for milling with a steady and constant weight on bit throughout the wellbore for removal of ball seat restrictions. This paper presents the latest achievements within e-line milling in Canada. The paper will discuss best practices of date as well as a discussion of e-line milling challenges through three case studies in Canada.

Find the full paper at https://www.onepetro.org/

SPE 163890-MS

Electric-line pipe-cutting operation optimizes completion removal, offshore Russia

In 2012, in its first field trial, an electric-line-conveyed mechanical cutting tool was used to cut completion tubing in a well off the east coast of Russia. This e-line cutting tool required no explosives, no chemicals, and no subsequent run to dress the top of the cut, as is typically the case with conventional pipe-cutting methods.

With these characteristics, the operator did not have to address any of the operational and administrative concerns or costs associated with conventional explosive methods such as: extra procedures, time for safe handling, limited vessel traffic, added security, nor additional operational rig time to dress off the flaired cut end before removal.

On a previous workover, the operator had experienced problems pulling a packer, debris was suspected in the annulus resulting from an explosive cut then subsequent run to dress off the flaired end. Therefore, they were looking for a different method for tubing cutting operations, one with reduced risk, reduced debris, and fewer post-cutting tasks prior to removing the tubing and completion.

In the first trial, the tool was used to successfully cut 4-1/2-inch, 12.6-lb/ft tubing in a 57° deviated well, at a depth of more than 2,133.6 m. Total operating time was six hours and actual cutting time approximately 80 minutes. The e-line cutting tool cut the tubing cleanly without flairing or creating substantial debris, leaving a smooth, beveled interior which can be fished without dressing off the cut using a conventional overshot. 

Find the full paper at https://www.onepetro.org/

SPE 163925

Optimal sand cleaning algorithms for planning and executing electric wireline suction tool operations

Conventional methods used for downhole sand or debris cleaning have considerable investments in economic costs and time. Scheduling these activities to minimize production interruptions and to maximize unrestricted flow is a constant challenge faced by production and flow assurance engineers in the Oil & Gas industry.

A sand and fill cleaning decision can be expressed as an optimization problem since its purpose is to maximize the production of the well to accomplish production goals at the end of a time period.

This paper presents optimization algorithms applied in dynamic programming to help in scheduling cleaning interventions for wells in order to maximize the continuous production under physical, technical and economic considerations while minimizing the investment cost of the total operation. A strategy will be presented which takes into account mainly the fixed costs but also the variable costs and sensitivity analysis that allow the model to better approximate reality. The strategy considers three options based on the costs of cleaning with either electric line or coiled tubing technology; 1) to completely remove a given volume of sand, 2) to clean to a minimum acceptable level or, 3) not to clean and allow sand volume increases to continue.

The cost to perform sand cleaning with a certain technology based on a mathematical function, considers the following requirements:
 the relationship between volume of sand produced per unit time, Vt (flow),
 (Vmax-Vmin) or the interval between Vmax in which production of oil is minimized and the Vmin for maximum production,
 the time horizon to perform the sand cleanings, and
 Points that make the operation unfeasible such as physical restrictions in the well or operator time/cost constraints.

This paper will also present two cases demonstrating the strategy to schedule cleaning interventions that achieves a set production goal.

Find the full paper at https://www.onepetro.org/


Using electric-line tools to clean wellbore laterals and perforate toes

Coiled tubing (CT) is invaluable equipment in shale oil/gas completion operations. From well cleanout to perforating and fracturing operations, CT does it all. However, with the boom in shale oil/gas development and the number of wells required to develop these unconventional resources, demand and cost for CT can be high and often availability can be limited.

In an effort to reduce completion costs and minimize CT use, reserving it for only those tasks that absolutely require it, an operator in the Eagle Ford shale decided to investigate alternative technologies for performing post-cementing well cleanup and toe perforating. The operator was aware of an electric-line (e-line), tractor-conveyed cleaning tool with a reverse circulating bit (RCB) that was being used for drifting and cleanout runs. These tools have been used successfully in Norway and Canada, offshore and on land, to clean out cement stringers and other debris from the wellbore, ensuring a clear path for the toe perforations, which follow. With these tasks successfully completed, the pumping down of frac plugs can be accomplished with confidence during multi-stage completion operations.

The operator decided to try the e-line technology on a five-well pilot project of cased, horizontal wells in the Eagle Ford development. This was the first time the technology was used in U.S. land operations. The e-line cleaning tool cleaned the wells, and the tractor-conveyed perforating guns reached the depth cleaned out by the e-line cleaning tool. On this pilot project, the average field time per well for an e-line cleanout and tractor-conveyed toe perforation was 24 hours. The pilot test was considered a success.

This paper discusses the details of the project and tool operations for each well, and the lessons learned and applied to each successive well in the pilot to develop a successful strategy for using these tools across a broad range of operating conditions.

Find the full paper at https://www.onepetro.org/


Electric-line milling systems removes stuck frac sleeve valve without damaging the subsurface safety valve landing nipple

This is a case study for a well intervention job that was conducted in the Prudhoe Bay Unit field, Alaska. It describes the successful use of an electric line milling system to remove a protective frac sleeve that was stuck in a subsurface safety valve (SSSV) landing nipple.

Past attempts to remove the sleeve with conventional methods were unsuccessful. Those attempts included slickline, coiled tubing (CT), and pulling 110,000 lbf with a workover rig using a through-tubing work string. At the time, the sleeve did not interfere with production, so it was left in the well. However, an unrelated tubing leak developed below the stuck frac sleeve. The well had to be shut in until the frac sleeve could be pulled to allow installation of a tubing patch.

Milling the frac sleeve with coiled tubing or replacing the entire tubing string with a workover rig was considered. However, cost and time could be reduced if the frac sleeve could be milled with an electric-line (e-line) conveyed bottomhole assembly (BHA).

The e-line tool string included a wireline release device, an electric-over-hydraulic tractor with stroking tool, electric milling motor, and burning shoe with integral centralizer and no-go. The burning shoe was designed to reduce the outside diameter (OD) of the frac sleeve but preserve the packing bore inside diameter (ID) of the SSSV landing nipple. The tractorstroker- miller tool string was run in the well and tagged the sleeve at 2,119 ft measured depth (MD) where milling continued for approximately 4 ½ hours. After E-line milling was completed, slickline was rigged up for fishing operations and successfully pulled the frac sleeve. The tubing repair was completed and the well was returned to production.

This intervention technology can be used in other wellbores requiring precision milling. The solution proved successful and is a cost-effective alternative to conventional methods for milling obstructions.

Find the full paper at https://www.onepetro.org/


Retrieval of an inflatable plug using only slickline and electric-line technology

When changing out completions in producing wells, inflatable tubing plugs are frequently used to control fluid loss and to protect equipment below the work area from the debris that results from pipe recovery and workover operations.

To navigate the narrow inside diameter (ID) of production tubing, the plug is run deflated; it is inflated at the desired measured depth to create a barrier during workover operations; and then, when work is complete, deflated again for removal.

To protect the inflatable plug—especially its retrieval mechanism—from falling-debris damage during workover, a common practice is to use a protective fill, such as sand or proppant, on top of the plug. Of course, before the plug can be removed, both the debris and the sand must first be removed. Traditionally a slickline bailer is used to remove the debris and sand up to the top of the plug’s external fishing neck. Then coiled tubing (CT) is used to wash away enough of the remaining sand from around the neck of the plug so that a slickline-deployed retrieving tool can latch onto the plug and retrieve it.

The operator had learned about a new electric-line, high-pressure suction tool that could be used instead of CT to remove the fill from around the plug’s external neck, thereby eliminating the extra time, cost, and HSE risks associated with CT use. During workover operations on a Gulf of Mexico well, the operator decided to put the electric-line suction tool to the test to determine its viability as a cost-effective alternative to CT.

This paper describes the successful use of the electric-line power suction tool to clean sand from around the inflatable packer’s external neck, which allowed the plug to be removed and production to resume.

Find the full paper at https://www.onepetro.org/


Productivity increases in manifa field using ct and hydraulic tractors to enhance stimulation

Discovered in 1957, Manifa field is a giant offshore field with six oil-bearing reservoirs that cover more than 800 km2 in the shallow waters northeast of Saudi Arabia. Typical wells in this field extend over 20,000 ft with more than two-thirds being considered extreme, extended reach wells that run beyond 24,000 ft. The longest high angle well in Saudi Arabia, 32,000 ft total depth (TD), is in this field.

Coiled tubing (CT) is a well-proven method to access these long, horizontal wells and is used frequently in the completion to perform matrix stimulation. However, it faces certain limitations that can prevent it from accessing the full TD in these extended reach wells. Reach capabilities depend on the size of the reel, the diameter of the coil, the material of the coil, the completion size and the wellbore geometry, to name a few. In order to extend the reach length of CT, hydraulic tractors in various sizes have successfully been run to pull the CT to TD in Manifa field. The CT tractor eliminates the aforementioned limitations by pulling the CT with forces of up to 4,000 lbs and removing the issues relating to helical buckling.

The benefits of extending the lateral reach capacity for the CT are multiple. Since the wells have already been drilled, there is the sunk cost associated to the depth of the well. If there is no method to get the CT to this depth, this cost cannot be capitalized on. Additional sunk costs are incurred by preparing, transporting and mixing all the stimulation fluids required to complete the entire well to the job site. If the CT hangs up far shorter than TD, these costs are again not recouped. Further, by not stimulating the well from the toe, or TD, the total production potential of the well is unrealized. In one of the wells, a world record was achieved when the CT tractor reached 28,759 ft. The operator wanted to access the open hole for stimulation, but without the 2 ½” CT tractor, the 2” CT would only have reached ~ 85% of the open hole section, leaving ~ 15% of the reservoir unstimulated. In another well, the CT tractor extended the reach of the CT by 5,610 ft, or 28%.

The CT tractor has proved itself capable of increasing the length of CT used on Manifa wells. This not only increases the operator’s return on sunk costs but more importantly, it increases the potential for full reservoir stimulation and boosts the productivity index significantly.

This paper documents the activity and successes that CT tractors have brought to Saudi Aramco in Manifa field.

Find the full paper at https://www.onepetro.org/


E-line heavy workovers in high latitude environments

Drilling and producing in high latitude environments is unforgiving. Temperatures often drop below -20°C and can reach as low as -50°C. Isolated locations or vast distances, extreme weather conditions and periods of deep darkness can restrict transportation of personnel and equipment. 

As a result, job complexity often leads to outright failure or an exponential increase in time to accomplish what would be a routine task in a normal environment. Often the best route to success and efficiency in these conditions is proven technologies and strategies. For over 80 years, e-line conveyance and tools have been refined and improved to become a very reliable means of data gathering and workovers, such as plug setting, debris removal, hardware milling, pipe recovery and so forth.

Modern electric line (e-line) capabilities can now accomplish what conventionally would have been rig- or coiled tubing-based workovers. In the North Sea, Canada, Alaska and Russia operators use e-line to perform ‘heavy’ workovers; explosion-free cutting of tubulars, scale and debris removal, milling through hardware such as nipples, failed isolation valves and flapper valves, and replacement of hardware, such as gas lift valves and Electric Submersible Pumps (ESP’s) in extended reach horizontals.
This paper discusses the benefits e-line tools can bring to accomplish ‘heavy’ workovers in a reliable manner in high latitude environments. Several case studies are presented to demonstrate these applications in practice.

Find the full paper at https://www.onepetro.org/


Using e-line conveyance in multi-stage fracturing to optimize efficiency: a case from bakken, ND

Multi-stage ‘plug-and-perf’ operations in the Bakken formation are conventionally performed using pump down wireline operations. However, when a restricted casing ID, coupled with road restrictions, strict budget and time constraints, and a long horizontal section prevented the use of conventional methods, an operator in North Dakota turned to e-line, tractor-based conveyance to get this USD 9M asset on line.

The operator needed to plug and perforate 26 zones from max depth at 21,740 ft up to the upper perforations at 11,830 ft to get the well on line swiftly. However, a 3.5 in. patch at 11,689 ft–11,709 ft meant the ID of the 4 1/2 in., 11.6# casing string was restricted, and thus the 4 1/2 in. plug could not be pumped in safely. Pumping the plug could cause it to set prematurely or get pumped off causing an expensive fishing job. Rig workover was deemed too time consuming due to the number of runs necessary and as a 2 in. coiled tubing (CT) string would only be able to reach about 17,000 ft, this option would have left 10 zones unperforated. To further complicate matters, spring thaw road weight restrictions were in place and the project was already over budget and behind schedule.

By turning to e-line tractor conveyance the 26 runs to ‘plug-and-perf’ were completed in just 14 days with no lost time. In addition, the patch was successfully negotiated, the plug set properly and the entire section was perforated. The swift and nimble nature of the e-line technology made it easy to overcome the logistical challenges and helped the operator with their timing and budget issues.

This paper will show why using e-line tractor conveyance was the right solution for this intervention where 146,608 ft were tractored with no lost time.

Find the full paper at https://www.onepetro.org/


Electric line tractor-based conveyance in high temperature wells: a collection of local case stories

Texas and Louisiana are not typically thought of as extreme environments, but the Haynesville and the Eagle Ford do have some hot and deep areas that are being developed. High temperature environments require specialized, robust intervention tools designed to withstand longer periods of extreme heat.

The industry’s definition for ‘high temperature’ ranges from 300°F to 400°F. Working in this environment requires careful preparation, as well as proven, reliable service providers and equipment. Established electric line tractor-based technologies running on AC power, as well as DC equipment have proven their application in these harsh and unforgiving environments. They offer additional benefits like reduced personnel and less heavy lifting, making these technologies inherently safer.

This paper will share the learnings from a number of local operations in which this electric line technology has been deployed, including advances with DC electronics and some examples of AC electronics cases ranging from conveyance of logging tools to plug and perforating for fracture stimulations.

In addition, this paper will examine the differences between AC and DC electric line equipment, their application in high-temperature environments, as well as discuss current trends within electronics for electric line equipment and future outlook for high-temperature equipment.

Find the full paper at https://www.onepetro.org/



Tubing retrievable surface controlled subsurface safety floating flapper remediation

A requirement within a conventional offshore well’s completion design per operator standard design and/or governmental regulation is the installation of a “subsurface safety device.” Among the list of permitted safety devices, subsurface safety valves (SSVs), if maintained properly, can fulfill such a requirement in well control and isolation.

Subsurface safety valves can easily be damaged during through-tubing (wireline, coiled tubing [CT], etc.) deployment through the valve if steps, such as equalization before opening, slowing toolstring running speed, etc., are not taken to properly safeguard valve integrity. A problem that could occur during these deployments, specifically in reference to the SSV flapper-type valve, is shearing of the hinge pin on which the valve flapper rotates, allowing the flapper to “float” in a cavity directly below its rotation point, creating an effective downhole obstruction.

A traditional intervention operation to repair this includes using a slickline (SL) rotating wedge to manipulate the flapper to a position that will allow a subsequent, suitably 3 sized sleeve installation through the cavity, bypassing the flapper. This will allow for both toolstring deployment past the obstruction to assist in future up-hole re-completion operations and continued production without slugging from unexpected valve flapper reseating.

This paper discusses a case history in which the above-mentioned conventional SL manipulation toolstring was deemed not suitable, as it was currently designed for a small cavity-type Tubing Retrievable Surface Controlled Subsurface Safety Valve (TRSCSSV), and alternative intervention means were developed. Five full-scale4 tests were performed with four different toolstrings (one SL and three electric line [EL]) engineered to provide a method of inserting a bypass sleeve with predetermined minimum inside diameter requirements for future tubing cutter deployment. Of the four toolstring options developed, two were deemed field ready and deployed with the offshore operation itself, while the other two required additional engineered modifications. Details of the successful intervention deployment are also given in which desired flapper orientation and isolation was not only achieved by toolstring manipulation but also by well-production characteristics.

Find the full paper at https://www.onepetro.org/


Improved zonal isolation in open hole applications

Achieving effective zonal isolation within long reach horizontal wells via conventional means, such as cement or swell packers, is becoming increasingly challenging to the industry. The longer step outs limit the Equivalent Circulation Density (ECD) due to frac/pore pressure limitations. Subsequent complex stimulation operations impose higher differential pressure (dP) across the packers.

To address these challenges, a novel design was introduced, effectively creating an expandable metal, sleeve-type annular barrier that allows cementless completions and effective zonal isolation. The design of the new annular barriers, assembled on a full bore liner, minimizes the running outside diameter (OD) whilst delivering a high differential pressure seal even within a washed out hole.

The qualification process was designed to meet the International Organization for Standardization ISO14310 V3 standard and to simulate the life cycle of the packer during acid stimulation and later-life water management.

The benefits to operators include increased reliability and certainty for success, both in the short-term and over the life of the wells.

This paper reports recent implementation of the new annular barrier to meet the unique challenges of annular high pressure containment. Findings are supported by specific case examples, and the paper includes a discussion on design, application and performance.

Find the full paper at https://www.onepetro.org/


World's first hydrate plug milling on e-line

Operators often struggle with a complex phenomenon causing unwanted and often unpredicted hydrate plugs to form in producing or injection wells, blocking production and re-entry to the well. Conventional remediation methods can be costly, time consuming, and are often ineffective.

This paper will share the knowledge gained from a world’s first operation, demonstrating that hydrates can be milled using electric line (e-line) tools. The operation was performed from a Vessel Fit for Purpose (VFFP) as a Riserless Light Well Intervention (RLWI) operation in the North Sea, offshore UK.

A hydrate plug was tagged below the subsea tree in a water injection well. This unconventional solution was chosen to restore injectivity to wellbore and minimize non-productive time (NPT). Unfortunately, during the operation, harsh weather caused operations to be stopped due to safety issues, and prevented removal of the entire hydrate plug. At that point, re-establishing functionality to the downhole safety valve became a major issue. Fortunately, in less than 20 hours of milling time 173 ft (52 m) of hydrates were removed on e-line and the operator was able to re-establish the functionality of the downhole safety valve.

E-line technology provided a swift and accurate resolution to the problem, proving that hydrates can be dealt with as easily as doing any other e-line intervention and that the technology can be run in a ‘live’ well under pressure.

Find the full paper at https://www.onepetro.org/


Optimizing efficiency in horizontal, multi-stage fracturing operations through e-line conveyance - case study from the bakken

In the Bakken, pump-down perforating has been the preferred solution for multi-stage ‘plug & perf’ operations for years. However, when an operator in a Bakken, North Dakota field was faced with a restricted inner diameter, they turned to an unconventional solution of using e-line, tractor-based conveyance.

The operation was a success and more such operations have been run. This paper will present the lessons learned from these operations, as well as discuss the applicability and efficiency gains of e-line, tractor-based conveyance. Best practice consideration will be proposed for future plug & perf operations in horizontal wells.

Several challenges led to the initial decision to select the tractor-conveyed solution. Poor road conditions made the logistics of heavy equipment difficult, and coupled with severe time constraints and strict budget considerations the e-line solution became the preferred choice. This decision enabled the operator to get this USD 9M asset on production in a timely manner.


A 3.6 in. patch was restricting the inner diameter of a 4½ in., 11.6# casing string. The operator needed to plug and perforate 26 zones horizontally from 21,740 ft up to 11,830 ft to get the well on-line quickly. Pumping the 4½ in. plug was not considered an option due to the risk of premature setting or pumping off plug and/or guns resulting in expensive and time consuming fishing operations. Coiled tubing would only be able to reach the first 16 zones leaving 10 zones non-perforated. Rig operations would be too time consuming and costly.

The 26 run, e-line operation was completed in 14 days with no conveyance mis-runs or lost time but only one gun mis-fire. The well was brought on-line quickly and the logistical challenges easily overcome due to the lightweight nature of the e-line technology. As an added bonus the operation offered several HSE benefits stemming from the low footprint, reduced personnel requirements, and less heavy lifting. 

Find the full paper at https://www.onepetro.org/

SPWLA 1640

Open hole, high angle tractor conveyance, a collection of case stories

Tractor-based conveyance and intervention systems for horizontal and high angle well operations have been in use for nearly 20 years. The first open hole (OH) application of a tractor was introduced to the industry in 1999. Since then, there have been many attempts to tractor in open holes with mixed results.

This paper will share the lessons learned and best practices derived from 15 years of OH tractoring operations. It will examine the track record of OH conveyance in several countries, including operations in the Middle East and in unconventional wells in the USA, describe the success factors, review rock strength issues and compare the risks of tractor-based conveyance to drill pipe conveyance.

Building on experience, success factor analyses and best practice guidelines, the success rate of OH tractoring has steadily improved over the years. One of the traditional limiting factors is the diameter of the OH, which can be beyond the reach of the tractor arms or wheels, either due to large bit sizes or enlarged boreholes caused by washouts. A new generation tractor was introduced in 2010 to address this issue. With an outer diameter of 4 1/2” and an operational OH diameter from 4.8” – 18” this tractor has made another step improvement in the success rate of OH tractoring.

This paper will also review the tractor-based OH conveyance logging services including triple combos, production logging tools, formation imaging logs as well as formation testing.

Find the full paper at https://www.onepetro.org/


Milling of isolation valve with wireline conveyed technology

A revolutionary drilling technique has emerged allowing drilling with electric wireline utilising metal machining technology in combination with field proven Well Tractor

As the Well Tractor technology evolved and confidence was gained during the past several years, the application of a cost efficient method for milling of specific downhole hardware (i.e. valves, plugs etc.) as an alternative to existing methods has emerged. The technology is specifically needed on offshore installations where the logistical limitations are high. The article will describe the actual operation and the process of developing the technology.

The first ever operation involving the milling of a blocked borehole on wireline was conducted in late 2003 in an oil producer on a North Sea platform. A single plate isolation valve was stuck in closed position and it was imperative to get the oil producing well on-stream at short notice.

Find the full paper at https://www.onepetro.org/

SPE 13808

Robotics for Horizontal Image Acquisition in Ultra Slim Wells in Saudi Arabia

The cost savings that are possible by sidetracking existing well bores make the drilling and completion of ultra slim lateral wells very desirable. Obtaining image logs from horizontal wells, less than 6” diameter, has always been a challenge, because the size of conventional borehole imaging tools that currently exist on the market are simply too large. In addition, conventional deployment methods limit efficient rig time utilization and ultimately lead to higher cost. 

New conveyance and logging technology from Welltec® (the Well Tractor®) and Weatherford (The Compact Micro Imager – CMI) allows operators to obtain excellent image logs in slim wells as small as 3 inches in diameter. Image logs are required to properly understand fracture details and to help in future drilling and completion decisions.

This paper describes the logging operational experience of the CMI and the world’s first slim hole imaging logs in Saudi Arabia deployed by the wireline tractor 218XR (XR: Extended Reach) in an open hole horizontal section.

Find the full paper at https://www.onepetro.org/