Negative Operational LL with Faroe

Rungne (30/6-30) – P&A

What happened:

The 18 3/4″ HP housing lock ring released after cutting the 20″ casing with 20 mt overpull. Following risk assessment, re-landed and re-angaged lock ring, adjusted overpull to just exceed string weight plus calculated weight of PGB, 30″ x 20″ stubs and WHHs, reasoning being to maintain tension, but minimize risk of possibly weakened lock ring releasing again, requiring extra trips and changes to BHAs to cut and fish strings individually.

What was planned:

Pull 20″x30″ casing/WH

What was learned:

For the future, Weatherford has recommended to cut the Wellheads by string rotation and limit the overpull to a minimum. We also suggest that during cutting, all weight should be set down to allow the lock ring to extract back to original position if the vibration and tension has made the lock ring to move inwards.Welding of anti-rotation fins in the 30″ Extension joint and on the 20″ Extension joint is still recommended, this will prevent rotation between the Wellheads

What actions are required:

Include in DOPs in future regarding P&A with MOST tool.