Fishing to Recover Lost Wire Successful | Schlumberger
Case Study
North Sea, United Kingdom, Europe, Offshore

After several attempts to clear a long-lost fish using various intervention methods, solutions provided by Peak Well Systems enabled the successful recovery of 11,575 ft pf 0.125-in slickline from a well, making plug and abandonment (P&A) possible.

Well-Safe Solutions Recovers 11,575 ft of Slickline Lost in a Well After 15 Years

Fish removal with Peak Well Systems, a Schlumberger company, allowed plug and abandonment of North Sea well

Stuck fish hindered P&A operations

Well-Safe Solutions wanted to recover a 15-year-old fish to clear the tubing to below 15,030 ft of any 0.125-in GD31MO™ slickline in preparation to plug and abandon the well.

Removing the fish could be cost restrictive

Two previous fishing operations (using a three-leg grab and subsequently braided cable) attempted to recover the wire lost in the hole but were unsuccessful. Recovering the fish would then involve mobilizing coiled tubing, which is not best suited to recover wireline and requires a larger footprint to rig up. This would also cause a longer fishing operation because of the time it takes to trip the coil in and out of the well, increasing cost. The condition of the wire and fish downhole could have deteriorated, further complicating fishing operations. Due to the complexities of heavy-duty fishing, the operation would be carried out using the derrick.

Fishing failed to recover the fish

The initial operation entailed a drift run (static survey). The slickline ran 2- × 1 7/8-in memory BHA and bottomhole temperature (BHT) gauges completed with a 2-in sample bailer to 17,168-ft holdup depth and performed gradient stops while pulling out of hole (POOH). After performing the last gradient stop in the liner, while also trying to continue to POOH, the pickup weight (PUW) increased.

The toolstring was run back in hole ±50 ft to try to lubricate the stuffing box packings. However, high PUW was still experienced. Slickline worked the toolstring back into the wireline entry guide (WEG) tubing, but the PUW increased from 1,200 lbm to 1,400 lbm, and the wire parted at the surface. At this point, ~14,160 ft of GD31MO wire and a 1 7/8-in toolstring complete with gauges and a bailer were lost in the hole.

An initial fishing attempt in 2006 revealed that the wire was balled up using a three-leg wire grab, but the operator and third-party slickline provider were unable to recover the fish. The grab was left downhole at 3,147 ft, as well as a 5 1/2-in tubing stop set at 3,143 ft. Another attempt in 2015 involved using a 7/32-in braided cable and a 2 1/2-in toolstring. The 5 1/2-in tubing stop set at 3,143 ft was recovered, and a 4.015-in lead impression block (LIB) tagged the wire grab. After five separate fishing runs with a wire grab (76 ft + 20 ft + 15 ft + 100 ft + 64 ft), 275 ft of wire was recovered. The wire grab was placed back in the well baited into top of wire at 3,855 ft, and a 5 1/2-in tubing stop was set at 3,852 ft.

A 5 1/2-in tubing stop, 4.100-in three-leg wire grab, ~13,885 ft of GD31MO wire, and a 1 7/8-in toolstring complete with gauges and a bailer were left in the hole.

Strategic project planning and execution enables better fishing operation

To recover the fish, initial planning involved reviewing the history and sequence of events that led to leaving the fish downhole, as well as the unsuccessful attempts to retrieve it. After the review, a comprehensive technical proposal was written based on the knowledge and experience gained from daily involvement in the planning and execution of fishing operations. The plan was reviewed and approved by Well-Safe Solutions and then implemented by Peak Well Systems. Along with a team that specializes in heavy-duty fishing operations, Peak Well Systems has a flying squad that can mobilize quickly worldwide to plan and provide onshore support.

Stuck fish is successfully removed

In 2022, after recovering the 5 1/2-in tubing stop from the well, 11,575 ft of 0.125-in slickline was recovered in 21 wire fishing runs. These runs involved back-feeding the recovered wire to a slickline unit. The tubing was then swept to the WEG for any loose wire and depths correlated with the digital slickline.

After a total of 26 runs the well was confirmed clear of wire. This made it possible to place a deep-set plug and commence the P&A program.

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