The Deepwater Horizon oil spill – also know as “The BP Oil Spill” or the “BP Gulf Oil Spill” is a catastrophic oil spill from an oil-drilling platform in the Gulf of Mexico. It gushed oil into the sea for three months in 2010 before being capped. This had a huge affect on the environment and the damage is still being assessed. The oil spill was the largest accidental marine oil spill in the history of the oil industry.
The Deepwater Horizon rig exploded April 20, 2010. It was drilling on the BP-operated “Macondo Prospect”. The explosion killed 11 men working on the platform and injured 17 others.
On July 15, the leak was stopped by capping the gushing wellhead. But not before it had released about 4.9 million barrels or 205.8 million gallons of crude oil into the sea. It’s been estimated that 53,000 barrels per day were escaping from the well before it was finally capped.
The spill caused extensive damage to marine and wildlife habitats as well as the Gulf of Mexico’s fishing and tourism industries. By late November 2010, 4,200 square miles (11,000 km2) of the Gulf were re-closed to shrimping after tar balls were found in shrimpers’ nets. The total amount of Louisiana shoreline impacted by oil grew from 287 miles (462 km) in July to 320 miles (510 km) in late November 2010. In January 2011, an oil spill commissioner reported that tar balls continue to wash up, oil sheen trails are seen in the wake of fishing boats, wetlands marsh grass remains fouled and dying, and that crude oil lies offshore in deep water and in fine silts and sands onshore. Oil was still being found on the seafloor in late February 2011.
Skimmer ships, floating containment booms, anchored barriers, sand-filled barricades along shorelines, and dispersants were used in an attempt to protect hundreds of miles of beaches, wetlands, and estuaries from the spreading oil. Scientists have also reported immense underwater plumes of dissolved oil not visible at the surface as well as an 80-square-mile (210 km2) “kill zone” surrounding the blown well.
The U.S. Government has officially cited BP as being responsible for the Deepwater Horizon oil spill and are holding the company accountable for all cleanup costs and damage to the environment and local industry.
From Wikipedia –
The Deepwater Horizon was a 9-year-old semi-submersible mobile offshore drilling unit, a massive floating, dynamically positioned drilling rig that could operate in waters up to 8,000 feet (2,400 m) deep and drill down to 30,000 feet (9,100 m). The rig was built by South Korean company Hyundai Heavy Industries. It was owned by Transocean, operated under the Marshallese flag of convenience, and was under lease to BP from March 2008 to September 2013. At the time of the explosion, it was drilling an exploratory well at a water depth of approximately 5,000 feet (1,500 m) in the Macondo Prospect, located in the Mississippi Canyon Block 252 of the Gulf of Mexico in the United States exclusive economic zone about 41 miles (66 km) off the Louisiana coast. Production casing was being installed and cemented by Halliburton Energy Services. Once the cementing was complete, the well would have been tested for integrity and a cement plug set, after which no further activities would take place until the well was later activated as a subsea producer. At this point, Halliburton modelling systems were used several days running to design the cement slurry mix and ascertain what other supports were needed in the well bore. BP is the operator and principal developer of the Macondo Prospect with a 65% share, while 25% is owned by Anadarko Petroleum Corporation, and 10% by MOEX Offshore 2007, a unit of Mitsui.[31] BP leased the mineral rights for Macondo at the Minerals Management Service’s lease sale in March 2008.
Explosion
At approximately 9:45 p.m. CDT, on April 20, 2010, methane gas from the well, under high pressure, shot all the way up and out of the drill column, expanded onto the platform, and then ignited and exploded. Fire then engulfed the platform. Most of the workers escaped the rig by lifeboat and were subsequently evacuated by boat or airlifted by helicopter for medical treatment; however, eleven workers were never found despite a three-day Coast Guard search operation, and are presumed to have died in the explosion. Efforts by multiple ships to douse the flames were unsuccessful. After burning for approximately 36 hours, the Deepwater Horizon sank on the morning of April 22, 2010.
Volume and extent of oil spill
An oil leak was discovered on the afternoon of April 22 when a large oil slick began to spread at the former rig site. According to the Flow Rate Technical Group, the leak amounted to about 4.9 million barrels (205.8 million gallons) of oil exceeding the 1989 Exxon Valdez oil spill as the largest ever to originate in U.S.-controlled waters and the 1979 Ixtoc I oil spill as the largest spill in the Gulf of Mexico.
Spill flow rateIn its permit to drill the well, BP estimated the worst case flow at 162,000 barrels per day (25,800 m3/d). Immediately after the explosion, BP and the United States Coast Guard did not estimate any oil leaking from the sunken rig or from the well. On April 24, Coast Guard Rear Admiral Mary Landry announced that a damaged wellhead was indeed leaking. She stated that “the leak was a new discovery but could have begun when the offshore platform sank … two days after the initial explosion.” Initial estimates by Coast Guard and BP officials, based on remotely operated vehicles as well as the oil slick size, indicated the leak was as much as 1,000 barrels per day (160 m3/d). Outside scientists quickly produced higher estimates, which presaged later increases in official numbers. Official estimates increased from 1,000 to 5,000 barrels per day (160 to 790 m3/d) on April 29, to 12,000 to 19,000 barrels per day (1,900 to 3,000 m3/d) on May 27, to 25,000 to 30,000 barrels per day (4,000 to 4,800 m3/d) on June 10, and to between 35,000 and 60,000 barrels per day (5,600 and 9,500 m3/d), on June 15. Internal BP documents, released by Congress, estimated the flow could be as much as 100,000 barrels per day (16,000 m3/d), if the blowout preventer and wellhead were removed and if restrictions were incorrectly modeled.
