Scientists offer varied estimates, all high, on size of BP oil leak

Cleanup and containment efforts continue at the Gulf of Mexico site of the oil spill following the Deepwater Horizon explosion.

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By Joel Achenbach and Juliet Eilperin
Friday, June 11, 2010

Pick a number: 12,600 barrels . . . 20,000 . . . 21,500 . . . 25,000 . . . 30,000 . . . 40,000 . . . 50,000. Scientists put every one of those numbers in play Thursday as they struggled to come up with a solid estimate of how much oil is gushing each day from the black geyser at the bottom of the Gulf of Mexico.

The one scientific certainty: It's a lot -- and more than some of the same scientists thought just a couple of weeks ago. It's so much that the crews trying to siphon it to the surface are going to need a bigger boat.

Early in the crisis, BP and the federal government repeatedly said that the Deepwater Horizon well was spewing about 5,000 barrels (210,000 gallons) a day into the gulf. But the new estimates, released Thursday by government-appointed scientists, show that the well most likely produces 5,000 barrels before breakfast.

One team that has studied video taken of the leaking riser pipe before it was cut and capped last week has concluded that the well was most likely producing 25,000 to 30,000 barrels a day. If that estimate is on target, and if the flow has been more or less consistent since the April 20 blowout, the hydrocarbon reservoir 2 1/2 miles below the sea floor has gushed five to six times the amount spilled in Alaskan waters in 1989 by the Exxon Valdez.

Put it another way: It's roughly one Valdez spill every week. Nearly two Olympic-size swimming pools of oil every day.

Another scientific team, which analyzed satellite images, has come up with a somewhat more modest estimate of 12,600 to 21,500 barrels a day, just a slight uptick from the team's earlier finding.

Or the flow could be much higher still: A team led by scientists from the Woods Hole Oceanographic Institution has studied the leak with instruments normally used in research on deep-sea hydrothermal vents. Its initial estimate puts the flow at 25,000 to 50,000 barrels a day, said U.S. Geological Survey Director Marcia McNutt, who leads the teams of scientists collectively known as the Flow Rate Technical Group.

"These numbers are all over the board," she said in a conference call with reporters.

In response to a question, McNutt said that 20,000 to 40,000 barrels is the most plausible range, but she emphasized that the findings are preliminary and that the techniques have inherent limitations.

The flow rate is significant on several fronts. First, it gives the government and BP a sense of how much capacity they'll need among surface ships to handle all the oil gushing out of the well and up a pipe to the Discoverer Enterprise drill ship, which is capable of processing about 18,000 barrels a day. Other ships are being added to the effort.

Second, the fines that BP faces for polluting the gulf will be tied to how much oil has leaked.

Third, the higher figures call into question the circumstances that led to the much lower estimates of the spill early in the crisis. On April 28, after having received estimates of the size of the spill from BP and the National Oceanic and Atmospheric Administration, the Coast Guard announced the 5,000-barrels-a-day estimate. Not until May 27 did the flow rate group increase the estimate to 12,000 to 25,000 barrels.


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