BP Plc’s crippled Macondo oil well spewed 4.1 million barrels of crude into the Gulf of Mexico during the 87 days before it was capped, a team of scientists said, making it the world’s largest accidental offshore spill.
BP siphoned off an additional 800,000 barrels from when the well exploded on April 20 to when it was capped on July 15, the U.S. government-appointed group said yesterday in its latest estimate of the worst oil spill in U.S. history.
The Macondo spill exceeds the 3.3 million barrels that the Royal Swedish Academy of Sciences estimated leaked from Mexico’s Ixtoc-1 well in the Bay of Campeche after a blowout in 1979. The world’s worst spill was in the 1991 Persian Gulf War when retreating Iraqi forces opened oil pumps, causing the release of 6 million barrels, according to the U.S. Environmental Protection Agency.
“The number should be thought of as our best estimate,” Ira Leifer, a University of California, Santa Barbara researcher and one of the scientists on the team appointed by the U.S. Energy Department, said in a telephone interview yesterday.
Fines Per Barrel
The new numbers could be used to help determine how much London-based BP is penalized because federal law requires that companies that spill oil into the ocean pay a per-barrel fine.
The fine could range from at least $1,100 per barrel to as much as $4,300 per barrel under the Clean Water Act if gross negligence is found, according to an e-mailed statement from U.S. Representative Edward Markey, a Democrat from Massachusetts and chairman of the Select Committee on Energy Independence and Global Warming.
Based on the flow team’s estimates and using Markey’s figures, fines could range from $4.5 billion to $17.6 billion.
The blast at Macondo killed 11 workers and destroyed the Deepwater Horizon rig that BP hired from Transocean Ltd. The disaster prompted BP to report a record loss for the second quarter, cost BP Chief Executive Officer Tony Hayward his job and had oiled 641 miles (1,030 kilometers) of Gulf coastline as of yesterday.
The amount of oil estimated to have escaped into the ocean from Macondo is about 16 times the amount from the Exxon Valdez, which leaked an estimated 257,000 barrels in a 1989 accident off Alaska.
The well was gushing about 62,000 barrels a day when it started leaking and about 53,000 barrels when it was capped on July 15, according to an e-mailed statement from the U.S. government’s joint information center. The estimate made using pressure readings and oil reservoir modeling is an update from the group’s range of 35,000 to 60,000 barrels a day given June 15.
“At certain moments, it was flowing a lot higher and a lot lower,” Leifer said. The flow decreased as the reservoir of oil and gas feeding Macondo became depleted, according to the researchers. The team’s estimate has an error margin of plus or minus 10 percent, it said.
“BP doesn’t have its own estimate of its flow rate or an assessment of the new report,” Elizabeth Adams, a spokeswoman for BP, said by telephone yesterday.
BP and the U.S. Coast Guard estimated the leak at 1,000 barrels a day on April 24. They increased that to 5,000 barrels April 28 after oil was found to be escaping from two points.
“The revised estimates are part of this administration’s ongoing commitment to ensuring that we have the most accurate information possible,” U.S. Energy Secretary Steven Chu said in yesterday’s statement.
“It’s the most solid estimate we’ve had and very troubling that they would come in at the high end of the range,” Ian MacDonald, a professor of oceanography at Florida State University in Tallahassee, said in an interview yesterday.
“As long as it has taken us to get a decent estimate to figure how much oil is coming out, it is going to take many, many times longer than that to figure out what it did to the ecosystem,” MacDonald said.
BP continues to work on a permanent plug for the well. A test of pumps at the site and the start of an attempt to plug the well permanently from the top will be delayed until today after a hydraulic leak was discovered in the system controlling the cap placed over Macondo, BP said in an e- mailed statement late yesterday.
The test will determine whether oil and gas trapped in the sealed well can be pushed back into the reservoir, BP Senior Vice President Kent Wells said yesterday on a conference call with reporters.
After the test, the company will begin injecting drilling mud with the goal of clogging the oil and gas reservoir, a procedure known as a static kill. Work on this may continue into tomorrow, Wells said.
The static kill will help BP determine whether to try to plug the well from the top with cement this week, or inject cement from the bottom, about 13,000 feet below the Ocean floor, using a relief well that may intercept the damaged hole between Aug. 11 and Aug. 13.
Regardless of the result of the test, BP will continue drilling the relief well it began in May to intercept the damaged bore, Wells said.