Technical papers
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.
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.
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.
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.
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;
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.
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.
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.
Find the full paper at https://www.onepetro.org/
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Method:
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.
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.
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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 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.
Find the full paper at https://www.onepetro.org/
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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).
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.
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.
Introduction
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
technology.
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.
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.