The Deepwater Champion, working for ExxonMobil in the U.S. Gulf of Mexico, successfully removed its first subsea christmas tree utilizing an active heave compensated knuckle-boom crane. The operation, meticulously planned through coordination between Transocean, ExxonMobil and FMC Technologies, was completed with zero health, safety, or environmental incidents. The subsea tree, which weighed 90,000 pounds in the air, was removed from a water depth of 4,856 feet using an NOV 165 MT active-heave compensated crane and placed on the deck of a waiting supply vessel.
The success of the operation was of significant value added to the Deepwater Champion’s customer. By utilizing the rig’s asset, the customer saved the time and expense of bringing in a specialized boat to perform the lift. It also eliminated rig non-productive time of having to wait for a boat to remove the tree, and instead maximized the DWC’s dual-activity capability. The rig used its forward rotary to disconnect its blowout preventer from the christmas tree and lift it 30 feet above any subsea infrastructure. With both the blowout preventer and the christmas tree hanging off of the sea floor, the Champion maneuvered to a safe lifting zone to remove the tree to surface. During the tree-removal process the rig’s drill crew utilized the aft rotary to continue making up the necessary tools and drill pipe to finish the customer’s well program.
All told, the operation saved the customer significant hours and costs, while validating the use of this crane for future well programs. The lead customer representative on board remarked that, “the DWC crew did a great job planning the operation. With good communication and the right equipment, we were able to successfully retrieve the Rockefeller HXT with the 165T AHC crane. This may have been a first for Transocean, but it felt like a standard operation for the DWC team. Great job!”
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