A guide for cost-effective rigless well abandonment project for platforms
Typically severed between 3-5 metres below the mud line, the well would be drifted with a camera if required, to ensure no obstructions at cut depth. Only then SABRE™ would be deployed to cut the well. After applying an ‘overpull’ to the well, typically 60 – 100 tonnes, the well is then cut, verified by the reduction in the applied overpull, and the SABRE™ cutting tool is then recovered.
The conductor is then hoisted up, and when the cylinders have been fully stroked, it is landed on the false rotary table. Held with slips, and with a safety clamp added for extra security, the tension ring is then released and repositioned and reset. The lifting process can then be restarted and the process repeated until the required length of conductor to be cut is above the false rotary table. This cut length is usually dependent on the capacity of the platform crane.
The conductor is then drilled and pinned in two places. It is then cut with casing bandsaws, and the cut joint is then laid out. Once it is on the deck, debris caps are secured to the open ends of the conductor, before the joint is backloaded on to the awaiting vessel. The work platform is then cleared of final debris and equipment before being re-positioned over the next well to be abandoned.
BEST PRACTICE FOR OTHER WELL ABANDONMENTS
The four-step guide to rigless platform well abandonments was outlined by Tom Mason on Claxton Engineering’s latest webinar Defining rigless and rig-based decommissioning, which can be watched again here.
On the webinar, Tom also lays out the best practice for subsea well abandonments, drilling rig-based abandonments and simultaneous operations (SIMOPS) too – as well as featuring case studies on how Claxton helped operators in the North Sea abandon their wells recently.
The 30-minute webinar, which is available to watch on demand, can be viewed here.
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