Well type
Producer
Temperature
99°C / 210°F
Pressure
5,221 psi / 360 bar
Fishing operations often require the application of great force to retrieve hardware or tools lost and stuck downhole.
Typically, operations to retrieve such items are carried out somewhat ‘blind,’ where one must rely heavily on the experience of the crew combined with low-level feedback/feel provided by the tools in use.
In this instance, an NCS operator had a parted toolstring with a stuck mill bit, which had been left downhole during a scale milling operation.
With a number of complexities to the fishing operation (including the level of required gripping force needed to attack the limited fishing point available on the fish), conventional tools on the market would not be able to complete the job, and so the well was temporarily abandoned.
In collaboration between Wellgrab AS, and Welltec®, a new and advanced downhole fishing solution was developed: a fully surface-controllable Electric/Electronic Release Fishing Tool (ERFT) combined with the Well Stroker®, offering up to 33,000 lbs. pulling capability and Surface Readout (SRO). This new solution matched all necessary criteria and provided a more technical approach to fishing.
The available engagement length of the fish was only 29 mm, but thorough systems integration testing confirmed that the ERFT would be able to hold the fish while the Well Stroker applied pulling force.
Wellgrab presented a sequence of solutions with a broad range of grapples and spears to account for different scenarios regarding the possible outcome; special emphasis was made on several contingency solutions in case the fish parted during the operation.
Other complexities, such as wellbore fill, deviation, and alignment of the fish, were identified and mitigated as part of a special risk assessment whereupon adjustments were made to optimize correct engagement of the tool onto the fish.
First, debris was removed from the wellbore over several runs using Welltec´s Well Cleaner® with Reverse Circulating Bit (RCB), Power Suction Tool (PST), and Heavy Debris Removal (HDR).
Access to the fish was confirmed by running a lead impression block, where the top of the fish was clearly visible.
On the fishing run itself, the first attempt revealed a bent finger on the grapple, which indicated access to the fish but limited wellbore ID. After modelling the findings, the OD of the bell guide was machined down to allow the tool to access the fish.
Following this simple adjustment, the Welltec® Wellgrab successfully engaged the fish, and with force applied by the Well Stroker, the fish was retrieved to surface.
The primary objective to retrieve the fish was achieved.
By providing real-time information on tool performance, the operation was greatly enhanced and carried out more quickly and efficiently in comparison to conventional fishing options.
By combining leading technologies from each company, Wellgrab and Welltec are making a unique value offering to energy industry operators, focusing on time and cost efficiencies through market-leading technology, opening up a new dimension to downhole fishing on electric wireline.
“The entire team’s in-depth knowledge, engagement and dedication spent in tedious iterations of testing, optimizing, and re-testing of the fishing solutions, prior to the operations, along with dedication and support during the operations, was key in recovering the fish swiftly and efficiently, once access to the fish was established. “
“Challenging well conditions with large amount of scale left on the tubing wall, made this a tedious operation. We would like to thank everyone involved in planning and execution of the operation. This proves that combining the best available solutions and technologies from different suppliers, working towards a common goal in a one-team setting, really makes a difference.”
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