Thursday, May 13, 2010

Gusher in the Gulf

Tuesday nine days ago, I commented toward the end of a post that The Christian Science Monitor had picked up on the rumors of serious underestimates of the gulf blowout's flow rate. The number from the US Coast Guard- largely unquestioned by the press- has been 5000 barrels per day for the last two weeks or more. BP acknowledged that buckles and kinks in the riser were probably constraining the flow, but that complete failure might lead to rates as much as 10 times that. Based on last Thursday's estimate of 2500 square miles of water covered by slicks, I made a couple of assumptions of average thickness, 1 mm and 0.1 mm. I'm not going to run through my calculations again, but if I remember, came up with estimates of 20 million gallons total spilled (which would amount to about 1.5 million gallons per day average (~35,700 bbl/day) for a mm, and a tenth of those numbers for 0.1 mm. Without more confidence about average thickness, there was no way for me to constrain the rate better... my upper range placed it in the neighborhood of the alarmist position, the lower range near the official numbers.

Based on the videos that BP released yesterday (apparently after resisting either acquiring them or releasing them for the last few weeks), The Guardian is reporting today that another method of analysis indicates that the flow rate- sit down, if you're not already- is around 70,000 barrels per day. 14 times the official estimate. That's a bit short of three million gallons per day, and the equivalent of an Exxon Valdez spill in less than four days. Every four days.
National Public Radio in the United States last night reported that the well is spewing up to 70,000 barrels of oil a day – the equivalent of an Exxon Valdez disaster every four days. Nearly 11 million gallons of oil were spilled in Alaska's Prince William Sound in 1989 when the Exxon Valdez tanker ran aground, oiling beaches and poisoning marine life for generations. NPR said scientific analysis of newly released video footage from the ocean floor suggested the gusher was 12 times more powerful than estimates offered so far by the Coast Guard or BP.

Its analysis was conducted by Steve Werely, an associate professor at Purdue University, using a technique called particle image velocimetry, a method was accurate to 20%. That puts the range of the oil spill from 56,000 to 84,000 barrels a day.
I guess the most positive thing I can say is I really, really hope someone screwed up their unit conversions, giving a result four orders of magnitude too high. But I sort of doubt it.

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