Trendsetter Vulcan Offshore (TVO) completed a unique tethered blowout preventer (TBOP) installation in the Gulf of America (GoA) to reduce wellhead fatigue in soft seabed conditions.
TVO’s proprietary technology was essential in enabling the execution of a recent completion project for an operator in the Central GoA. The Hercules TBOP system was originally devel-oped specifically to allow a deepwater floater fitted with a dynamic positioning system to work safely in shallow water. The basic system configuration employs four polyethylene-based teth-ers anchored to suction pile foundations on the seabed, arresting BOP stack motion above the wellhead and transferring loads to the tethering system, foundations, and seabed to substantially reduce wellhead cyclic stresses and enhance fatigue life.
Operations on this well, in nearly 4,000-ft water depth, were challenging due to the extremely soft seabed in the vicinity of the well, which created the potential for higher-than-normal fa-tigue loading on the well system. TVO’s tethering system was installed to allow wellhead fa-tigue to be managed with the rig BOPs installed and to provide stability to the well system dur-ing critical operations. This allowed operations to be successfully completed on a well with potentially elevated risk.