A well severance solution for three subsea tieback wells and eight dual-bore wells

Claxton (formerly Proserv FTS at the time of the project) used its abrasive water cutting technology to carry out severance of the multi-string cuts for chevron on three subsea tieback wells and eight dual-bore wells across three platforms.

The problem

As part of their Gulf of Thailand Asset Retirement Programme, Chevron was looking for a well severance solution for three subsea tieback wells and eight dual-bore wells across three platforms:

Subsea tieback wells – 7 in, 9 5/8 in, 20 in, 30 in
Dual-bore wells – 2 x 9-5/8 in cemented into a 30 in conductor

The main objective was to sever the wells below the mudline and recover for disposal as the final phase of the well abandonment process.

The solution

Based on the speed and reliability of our solution, Claxton (formerly Proserv FTS at the time of the project) proposed its abrasive water cutting technology to carry out severance of the multi-string cuts. That meant that once the well-services provider had started plugging the wells we could operate ‘offline’ and begin SIMOPS, hence off the critical path of the jack-up rig.

To do this, Claxton proposed to deploy the cutting tool using a modular deployment system rather than the rig crane or derrick facilities.

the result

In total, eight dual-bore and three tieback wells were severed 15 ft below the mudline.

As we were offline, our time did not extend the rig days/critical path offshore and the Claxton solution successfully completed all well severances where conventional methods failed.

Chevron was challenging in the way they approached P&A campaigns to be as efficient as possible and we adapted our deployment, recovery and proving methods to align with their vision.

The client believed this was one of the most demanding well abandonment campaigns they had carried out globally, so a testament to the capability of our equipment and offshore team.

“This was one of the most challenging platforms we have worked on which required a responsive and experienced company to help us deliver. We were impressed with Claxton’s [nee Proserv FTS] technology and its ability to sever some of the most difficult wells we have encountered.”

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