Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore oil drilling rig owned by Transocean. Built in 2001 in South Korea, in September 2009, the rig drilled the deepest oil well in history at a vertical depth of 35,050 ft. and measured depth of 35,055 ft. in the Tiber Oil Field at Keathley Canyon block 102, approximately 250 miles southeast of Houston, in 4,132 feet of water. On 20 April 2010, while drilling at the Macondo Prospect, an explosion on the rig caused by massive buildup of oil killed 11 crewmen and ignited a fireball visible from 35 miles away. The resulting fire could not be extinguished and, on 22 April 2010, Deepwater Horizon sank, leaving the well gushing at the seabed and causing the largest offshore oil spill in U.S. history.
1.The cement fails to protect the high pressure mud pipe: Either the primary or secondary cementing failed, pushing a huge column of natural gas into the well pipe.
2. Sea water got into the pipe and can no longer help control pressure: When the cement in the pipe failed, the natural gas rocketed to the surface, as the weakened mixture of mud and seawater did not have the pressure necessary to hold the gas back. The gas exploded the rig.
3.The blowout prevention Fails: With only seconds to react, rig operators fired off the shear ram, (which was used to stop a gusher if mud control is overwhelmed) but it only partially sheared the drill pipe. A joint may have been in the way, or the ram was fouled by pieces of casing or cement from the blowout. For days, remotely operated robots tried to fire off the ram manually, but failed.
The overall effect was BP’s complete and utter disregard of warning signs. Workers and inspectors constantly came to them about small problems. But BP did not bother to check up and fix these problems. If inspections were taken seriously, the fact that gauges in the control room were not working properly might have helped prevent the...