|
The ''Deepwater Horizon'' oil spill was discovered on the afternoon of 22 April 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 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.〔〔 BP has challenged this calculation saying that it is overestimated as it includes over of oil which was collected before it could enter the Gulf waters.〔 ==Spill flow rate== In its permit to drill the well, BP estimated the worst-case flow at .〔 Immediately after the explosion the USCG did not estimate any oil leaking from the sunken rig or from the well.〔 On 24 April, USCG 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 USCG and BP officials, based on remotely operated vehicles as well as the oil slick size, indicated the leak was as much as .〔 Outside scientists quickly produced higher estimates, which presaged later increases in official numbers.〔〔〔 Official estimates increased from on 29 April,〔〔 to on 27 May,〔〔〔 to on 10 June,〔〔〔 and to between , on 15 June.〔〔 Internal BP documents, released by Congress, estimated the flow could be as much as , if the blowout preventer and wellhead were removed and if restrictions were incorrectly modeled.〔〔 Official estimates were provided by the Flow Rate Technical Group—scientists from the National Oceanic Atmospheric Administration (NOAA), United States Geological Survey (USGS), Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), U.S. Department of Energy (DOE), and outside academics, led by USGS director Marcia McNutt.〔〔〔 The later estimates were believed to be more accurate because it was no longer necessary to measure multiple leaks, and because detailed pressure measurements and high-resolution video had become available.〔 According to BP, estimating the oil flow was very difficult as there was no underwater metering at the wellhead and because of the natural gas in the outflow.〔 The company had initially refused to allow scientists to perform more accurate, independent measurements, saying that it was not relevant to the response and that such efforts might distract from efforts to stem the flow.〔 Former EPA Administrator Carol Browner and Congressman Ed Markey (D-MA) both accused BP of having a vested financial interest in downplaying the size of the leak in part due to the fine they will have to pay based on the amount of leaked oil.〔 The final estimate reported that were escaping from the well just before it was capped on 15 July. It is believed that the daily flow rate diminished over time, starting at about and decreasing as the reservoir of hydrocarbons feeding the gusher was gradually depleted.〔 In a 3 December 2010, statement, BP claimed the government overestimated the size of the spill by between 20% and 50%. A document submitted by BP to the commission, NOAA, and The Justice Department says that "they rely on incomplete or inaccurate information, rest in large part on assumptions that have not been validated, and are subject to far greater uncertainties than have been acknowledged. Representative Edward Markey, a member of the House energy panel that is investigating the spill, said in a statement that BP has done whatever it could to avoid revealing the true flow rate of the spill. "With billions of dollars at stake, it is no surprise that they are now litigating the very numbers which they sought to impede." A BP spokesperson said that BP "fully intends to present its own estimate as soon as the information is available to get the science right."〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Volume and extent of the Deepwater Horizon oil spill」の詳細全文を読む スポンサード リンク
|