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Wel-lok™ technology scaled to plug and abandon offshore well in Gulf of Mexico

Published by , Editorial Assistant
Oilfield Technology,

BiSN, a leading supplier of downhole sealing solutions and technology to the global oil and gas industry, has eclipsed their own record for the largest bismuth plug with a recent deployment in the Gulf of Mexico. A permanent, gas-tight seal was required for a well with a 36” OD that was experiencing gas migration. In previous campaigns with Aker BP in Norway, BiSN had set the record for permanently sealing a 30” OD well in the North Sea.

To seal a well of this size, BiSN scaled its Wel-lok technology and operations to meet the needs of both the size of the tool and the production timeline requested by the operator. With potential environmental damage to be considered, it was essential to meet the timeline required by the operator. The Wel-lok tool required more than 10 000 kg of bismuth alloy and 2200 kg of thermite, bringing the total weight to over 20 000 kg.

BiSN meets the challenge of offshore rigless deployment

As the well had already been sealed using cement but was still experiencing gas migration, it was essential that BiSN deployed Wel-lok technology without using a rig and to avoid any potential environmental damage. An innovative deployment method was applied using a liftboat and remote operated vehicles (ROV) to guide the tool into place to be fired.

Once the tool was activated by timer, the bismuth alloy flowed, filling and sealing the cross section of the conductor pipe in under an hour. Upon solidification, the alloy expanded creating a mechanical gas tight seal. The burn time took approximately 55 minutes resulting in significant environmental benefits and cost savings for the operator. ROVs continued to observe the well for 20 hours with no evidence of further gas migration.

Paul Carragher, CEO of BiSN, said: “The success of this tool really speaks more about the flexibility and varied applications of BiSN’s Wel-lok technology, the size is just part of the story. By utilising BiSN’s technology, we ensured a permanent seal giving the supermajor operator peace of mind, saving them time as we were able to deploy from a liftboat and costs as a rig wasn’t necessary. We have now completed over 400 deployments worldwide with BiSN’s Wel-lok technology gaining significant momentum and I’m excited as we continue to expand the range of applications for which the technology can be used, as well as BiSN facilities and people worldwide to support the growth.”

Developing safe, permanent sealing technology continues

BiSN continues to refine and develop Wel-lok technology for a variety of well intervention, completion, and plug and abandonment applications. Currently, Wel-lok technology has been commercially applied to 11 different applications, including water shut off, cement repair, packer repair, and plug and abandonment.

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Mexico upstream news Offshore news