Located 150 miles (240 kilometres) south of New Orleans in the Gulf of Mexico, US, Thunder Horse is BP’s largest production and drilling platform in the region. It can house almost 300 workers in its living quarters. It can produce up to 250,000 barrels of oil a day and 200 million cubic feet of natural gas. The Thunder Horse South Expansion project adds a new subsea drill centre approximately two miles (three kilometres) from the Thunder Horse platform. Here, we take a look at the drilling and construction vessels involved:
This ultra-deepwater semisubmersible rig, owned by Transocean, drilled the first of the project’s three new wells. Instead of anchoring to the seafloor, the rig’s dynamic positioning system uses sensors and computer-controlled thrusters to hold the vessel steady while drilling operations progress.
Over a period of eight days (and with the help of the Grand Canyon II), Technip’s Deep Blue unspooled and lowered two new flowlines to the seabed to connect the existing drill centre below the Thunder Horse platform with the new drill centre, which ties together three new wells and an existing fourth well. BP and Technip used both traditional physical and advanced 3D simulation modelling techniques to develop the best solution to safely initiate the flowlines below Thunder Horse without affecting the platform’s production. Deep Blue is one of the world’s most technologically advanced ultra-deepwater pipelay and subsea construction vessels.
In support of Deep Blue, Grand Canyon II assisted with the ‘pull-in operations’, which included pulling in the end of the flowline and placing it in its final position below the platform. The vessel also performed the precommissioning work for the flowlines once they were installed on the seabed. This work involved flooding, cleaning and gauging the pipelines to ensure their integrity.
All of the project’s new subsea equipment, apart from flowlines, was installed by this multi-service subsea construction vessel—including production manifolds (used to commingle the flow of oil from multiple wells into the flowlines) and the jumpers (pipes that connect one piece of subsea equipment to another). The vessel is under long-term charter to BP for inspection, repair and maintenance of existing subsea facilities.