BP Operated Thunder Horse Semi-Submersible Platform, Gulf of Mexico, USA

Information Panel




Gulf of Mexico


United States


Drilling & Production Platform


Semi Submersible

Drilling Manager



Year Built




Thunder Horse is a BP operated platform, lying approximately 150 miles (240 km) southeast of New Orleans, in block 778/822 of the US Gulf of Mexico.  It sits in 6,040 ft (1,40m) of water.

BP holds the majority stake of 75% in both the Thunder Horse platform and Thunder Horse field, and is partnered by ExxonMobile (25%).



The Thunder Horse field was discovered in July 1999, after the Thunder Horse Discovery Well was drilled in Mississippi Canyon Block 778. This initial well was drilled to a depth of 25,770 feet (7,850 m), with two further wells being drilled to depths of 29,000 feet (8,800 m) and 26,000 feet (7,900 m), all from Transocean's drill ship Discoverer Enterprise. 

It is estimated that the Thunder Horse Field contains recoverable reserves of at least 1,000 million boe.

Although the reserves were vast, due to the complexities and technical challenges involved in the recovery, development of the field took time.  Up until that point, no field at such a depth had been developed.  Apart from the extreme water depth, the well was considered High Pressure High Temperature (HPHT), with downhole pressures at over 1,200 bars (120 MPa), and temperatures up to 135 °C (275 °F).

The Thunder Horse eventually came on stream in 14th June 2008, almost nine years after discovery, having cost over 5 billion USD.

Due to a wrongly installed valve in the ballast control system during construction, the platform experienced a dangerous 20 degree list in July 2005.  All personnel were evacuated.  After the problem was fixed and Thunder Horse righted, no damage was found to the platform.

Six weeks after the righting, Thunder Horse was hit by Hurricane Katrina.  Although this was practically a direct hit, due to the platforms design, no damage was sustained.



Thunder Horse is a Semi-Submersible, anchored to the sea bed.  It is the largest moored Semi-Submersible in the world, and contains all drilling and production facilities for both oil and gas.

The hull  having been built in South Korea by Daewoo Shipbuilding & Marine Engineering (DSME), was transported by DockWise's heavy lift ship, The Blue Merlin, to Ingleside, Texas, where all topside construction and fit out was undertaken by Kiewit Offshore Services.

Thunder Horse, like most platforms, was designed for the so called 100 year event.  Due to its robust design, it sustained no damage in 2005 after a direct hit from Hurricane Katrina.



Recoverable reserves from the Thunder Horse field are estimated to be 1,000 million boe.   Both oil and gas produce is sent via BP operated subsea pipelines to back to shore for refining.

At its peak in 2009, Thunder Horse was producing 250,000 barrels of oil a day.  This is thought to have declined by at least 40,000 barrels.



BP's Thunder Horse Semi-Submersible Platform

BP's Thunder Horse Semi-Submersible Platform

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