Jack-up Boat Well Decommissioning

Operator uses the Claxton SABRE™ subsea abrasive cutting system to reduce rig costs.

Responsible operators are actively plugging and abandoning offshore wells that have reached the end of their operational lives. This decommissioning work provides long-term protection for people and the environment, and helps to protect a company’s reputation and secure its licence to operate.

However, the economics of fulfilling well abandonment obligations can be challenging, particularly where a rig needs to be mobilised to allow the work to be performed safely.

BHP

Is a rig required?

The operator wanted a safe and cost-effective way to decommission a well in Morecambe Bay in the Irish Sea. Traditionally, this work scope, which included cleaning and dredging the well, placing cement barriers in the bore and cutting and recovering the casing, would require the use of a rig. However, the client wanted a safe and efficient solution that could be deployed from its existing jack-up workboat.

A cost-effective solution

Claxton provided well abandonment services that were deployed using a flexible line from the back of a boat, without the need for an expensive rig. These services included the use of the SABRE™ subsea abrasive cutting system, cement deployment equipment and packers. Claxton also supplied and managed third-party ROV and cementing services.

Critically, specialist tools and deployment equipment enabled the use of the relatively small, jack-up workboat, which was already available to the operator.

The flexible SABRE™ system uses high-pressure abrasive water jets at transonic speeds to cut through multiple cemented casings. Casings can be cut and recovered simultaneously or individually. The system has a low environmental impact, using only naturally occurring garnet, water and air in the jet.

Benefits

Claxton’s decommissioning, design engineering and offshore teams worked closely with its supply chain and the
operator to successfully abandon the well. The ability to perform the work from a jack-up boat removed the need to mobilise a rig, saving rig mobilisation and rental costs. Robert Leggett, Decommissioning Product Leader, Claxton, said,

Working with the client to successfully abandon the well was a pleasure. This project was particularly memorable, as we believe that we achieved a first with the placement of a cement barrier nearly 300 m below the mudline using a flexible line from a jack-up boat. Our experience with SABRE™ and related plug and abandonment services were key to to the project’s success. We have since worked with the client on numerous similar well abandonment assignments, strengthening our excellent long-term relationship.

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