GREAT YARMOUTH, UK – Claxton has developed an extension module for its Suspended Well Abandonment Tool (SWAT). This allows it and sister Acteon company, Offshore Installation Services (OIS), to set deeper environmental and intermediate barriers.
Neil Watson, SWAT product leader at Claxton, said the new module increases the range of wells that can be abandoned using the tool.
SWAT can be deployed from a vessel of opportunity through the moonpool, eliminating the need for a drilling rig. It is positioned on the wellhead and can perform casing perforation, recovery of drilling mud and placement of required cement barriers in the well.
The extension module allows cement to be positioned deeper within the well. A wiper plug is positioned before and after the cement column, ensuring 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.
During OIS’ most recent well abandonment campaign, the depth was 2,400 ft (731 m) below mudline – previously, the SWAT tool was limited to environmental barriers up to 600 ft (183 m) below mudline.
Earlier this year OIS completed its 18th multi-operator P&A campaign for Centrica Energy and Antrim Energy in the UK central North Sea, using the new extension module, abandoning 10 subsea wells in categories 1, 2.1 and 2.2 via the rigless method.
OIS conducted offshore operations from the anchor-handling tug supply vessel Island Valiant. During the first phase, the SWAT system was deployed through the vessel’s moonpool to perforate, circulate and set cement barriers in the bore and across all the casing annuli.
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