This paper describes the decision-making process and on-the-fly design strategy that paved the way for the successful and incident-free execution of a uniquely engineered kill and salvage operation in the Bay of Bengal. The seven-month project employed a 150 HP Remotely Operated Vehicle (ROV) to successfully secure a storm-damaged well and recover a 217-ton BOP stack from more than 800 ft of water.

The kill and salvage operation was initiated after a late-summer depression that generated surface and subsurface currents as high as 4.5 knots, eventually severed the riser near the BOP stack on the operator’s Sagar Bhushan drillship, which was completing the ONGC G-1-DB well. The unparalleled project overcame numerous technical challenges to unconventionally kill the well via stinger and retrieve the BOP, subsea tree and wellhead, while averting any potentially catastrophic HSE incidents.

The complexity of the operation was underscored with the on-location designing of an unprecedented procedure and specialized tools to kill the well where all post-storm subsurface components, including the BOP stack and drill pipe, were buried and resting horizontally. Practically all of the tools required had to be customized and fabricated on-board either the ROV-deployment vessel or drillship. These included everything from the customized stinger used to kill the well, to the cutters and heavyweight slings needed to raise the BOP stack.

The authors will systematically review the operation and the close communication between the operator and service provider that resulted in the decision to employ the unique kill and salvage procedure.

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