PERTH, Western Australia – Peak Well Systems, a specialist downhole tool provider, has been instrumental in fishing a parted tubing retrievable safety valve lockout tool for a major oil company in a southern North Sea well.
The downhole safety valve (DHSV) is a vital component on the completion that will isolate the surface from wellbore fluids in the event of an emergency. The company’s fishing package, including a high-strength, high-temperature magnet and retrievable overshot, recovered the safety valve lockout tool, which had parted down hole in the safety valve at a well depth of 534 ft (163 m).
Video footage established that the “bean can” mechanism (part of the safety valve lockout tool that keeps the flapper permanently in open position) had successfully locked out the DHSV. The sub-assembly housing on the bean can had fallen and was expected to be sitting in the 3.688-in. nipple at 8,155 ft (2,486 m).
To complicate matters, it was identified that the actuation dog of the lockout tool might hinder the retrieval of the housing by sitting across the top of the fish, thus preventing retrieval with a spear.
In response to the situation, Peak worked in close collaboration with the operator, providing technical support and discussing all the fishing options. The company provided layout drawings for various overshots and spears, operational procedures, and the rapid manufacture and delivery of the fishing tools to Great Yarmouth, UK.
For one contingency, a gauge cutter was modified to act as a sweeping tool for the actuation dog. In the event that it was needed, the gauge cutter would be rotated around the top of the sub-assembly by an indexing tool and would push the actuation dog back into the sub-assembly. A high-strength, high-temperature magnet was supplied for retrieval of the actuation dog and a 2.720-in. releasable spear for retrieval of the sub-assembly.
Steve Moir, Peak’s technical sales manager, said, “Our close collaboration with the client resulted in the fishing operation going exactly to plan. The magnet picked up the actuation dog and the releasable overshot speared the inner spring mandrel on the first attempt and pulled the fish to surface. The operator was delighted with the successful outcome.”