Claxton developed an extension module for its suspended well abandonment tool (SWAT), enabling Claxton and Acteon sister company, Offshore Installation Services Ltd. (OIS), to set deeper environmental and intermediate barriers.
The existing SWAT tool is deployed from a vessel of opportunity through the moonpool, eliminating the need for a drilling rig. It is positioned on the wellhead and then used to perform casing perforation, recovery of drilling mud and placement of the required cement barriers in the well.
SWAT utilizes the extension module to enable cement to be positioned even deeper within the well. A wiper plug is positioned before and after the cement column, which ensures that the wellbore is cleaned ahead of the cement. The lower plug forms a base for the column and slurry is uncontaminated when it enters the annulus. The cement is then displaced to the required depth in the well. In OIS’s most recent well abandonment campaign, the depth was 2400ft below mudline. This added depth capability significantly enhances well decommissioning capacity; previously, the SWAT tool was limited to environmental barriers up to 600ft below mudline, which limited the wells eligible for abandonment with SWAT.
“In combining our proven SWAT tool with the new extension module, we have significantly increased the range of wells that can be abandoned using SWAT. By providing our customers with more opportunities to opt for this rigless method, we enable them to reduce their well abandonment costs considerably,” said Neil Watson, SWAT product leader, Claxton.
OIS successfully completed its 18th multi-operator plug and abandonment campaign for Centrica Energy and Antrim Energy in the central North Sea, using Claxton’s new SWAT extension module. Ten subsea wells in categories 1, 2.1 and 2.2 were abandoned with the rigless method.
Image: Rendering of the SWAT Extension Module/Claxton
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