Gulf Spill 70,000 barrels a day

SUBHEAD: A mechanical engineering professor who studied the video of the leak estimates the flow to be 70,000 barrels a day — 14 times BP's estimate. Image above: Illustration, By Dan Swenson, of underwater situation at BP disaster. Source - USCG, NOAA, BP, Trasnocean. From (http://blog.skytruth.org/2010/04/gulf-oil-spill-6-million-gallons-per.html). By Bettina Boxall on 14 May 2010 in Los Angeles Times - (http://www.latimes.com/news/nationworld/nation/la-na-oil-spill-measure-20100514,0,1541851.story) A video released by BP this week has underscored questions about the rate at which oil is spewing from a broken pipe on the Gulf of Mexico seabed. BP and government officials have pegged the leak resulting from the Deepwater Horizon rig disaster at 5,000 barrels a day, or about 200,000 gallons. But a scientist who analyzed the video of the gushing pipe said Thursday the oil flow appeared to be much greater. "I spent a couple of hours this afternoon analyzing the video, and the number I get is 70,000 barrels a day coming out of that pipe," said Steve Wereley, a Purdue University mechanical engineering professor. Video above: "Crater Plume Gassing". Underwater footage of BP geyser of crude oil. From (http://www.youtube.com/watch?v=Y5hFPI4Y93U). Wereley, who has written a book on flow measurement, said his figure was an estimate that could be off by plus or minus 20%. "BP has said you can't measure this. I agree you can't measure [the flow] to a very high degree of precision," he added. "But that doesn't mean you can't get a good estimate. This estimate, I think, is much better than the 5,000 barrels a day they have previously been floating." In response to Wereley's estimate, Rep. Edward J. Markey (D-Mass.) said late Thursday that he would launch a formal inquiry into the matter. "I am concerned that an underestimation of the oil spill's flow may be impeding the ability to solve the leak and handle the management of the disaster," said Markey, a member of the House Energy and Commerce Committee. Wereley arrived at the number by comparing individual frames of the video and tracking how fast a swirl of spewing oil moved from one frame to another. He then calculated the flow based on the size of the pipe. He conducted the exercise after National Public Radio called him and asked whether the flow could be measured. The network reported Wereley's results Thursday. BP spokeswoman Rebecca Bernhard said the company is standing by the 5,000-barrel figure. "We look at the fact that it's coming out of the riser [pipe] in several ways. We look at it from satellite imagery, overflight observations and on-the-water observations." She said none of the methods were exact. "We said that from the beginning." Last week BP officials told members of Congress in closed-door briefings that the spill could amount to 60,000 barrels a day in a worst-case scenario.
Gulf Spill Worse Than Estimated Video above: "Lowering the Cofferdam". BP's failed attempt at a quick fix. From (http://www.youtube.com/watch?v=2JTM2QyAfCI) By Richard Harris on 14 May 2010 on NPR - (http://www.npr.org/templates/story/story.php?storyId=126809525) There's at least 10 times as much oil spilling into the Gulf of Mexico than official estimates suggest, according to an exclusive NPR analysis. At NPR's request, experts analyzed video that BP released Wednesday. Their findings suggest the BP spill is already far larger than the 1989 Exxon Valdez accident in Alaska, which spilled at least 250,000 barrels of oil. BP has said repeatedly that there is no reliable way to measure the oil spill in the Gulf of Mexico by looking at the oil gushing out of the pipe. But scientists say there are actually many proven techniques for doing just that. Steven Wereley, an associate professor at Purdue University, analyzed videotape of the sea-floor gusher using a technique called particle image velocimetry. A computer program simply tracks particles, and calculates how fast they are moving. Wereley put the BP video of the gusher into his computer. He made a few simple calculations and came up with an astonishing value for the rate of the oil spill: 70,000 barrels a day — much higher than the official estimate of 5,000 barrels a day. The method is accurate to a degree of plus or minus 20 percent. Given that uncertainty, the amount of material spewing from the pipe could range from 56,000 barrels to 84,000 barrels a day. It is important to note that it's not all oil. The short video BP released starts out with a shot of methane, but at the end it seems to be mostly oil. "There's potentially some fluctuation back and forth between methane and oil," Wereley said. But assuming that the lion's share of the material coming out the pipe is oil, Wereley's calculations show that the official estimates are too low. "We're talking more than a factor of 10 difference between what I calculate and the number that's being thrown around," he said. At least two other calculations support him. Timothy Crone, an associate research scientist at the Lamont-Doherty Earth Observatory, used another well-accepted method to calculate fluid flows. Crone says the flow is at least 50,000 barrels a day. Eugene Chaing, a professor of astrophysics at the University of California, Berkeley, got a similar answer just using pencil and paper. Without even having a sense of scale from the BP video, he correctly deduced that the diameter of the pipe was about 20 inches. And though his calculation is less precise than Wereley's, it is in the same ballpark. "I would peg it at around 20,000 to 100,000 barrels per day," he says. Chiang calls the current estimate of 5,000 barrels a day "almost certainly incorrect." Given this flow rate, it seems this is a spill of unprecedented proportions in U.S. waters. "It would just take a few days, at most a week, for it to exceed the Exxon Valdez's record," Chiang said. BP disputed these figures. "We've said all along that there's no way to estimate the flow coming out of the pipe accurately," said Bill Salvin, a BP spokesman. Instead, BP prefers to rely on measurements of oil on the sea surface made by the Coast Guard and the National Oceanic and Atmospheric Administration. Those are also contentious. Salvin also says these analyses should not assume that the oil is spewing from the 21-inch pipe, called a riser, shown in the video. "The drill pipe, from which the oil is rising, is actually a 9-inch pipe that rests within the riser," Slavin said. But Werleley says that fact doesn't skew his calculation. And though scientists say they hope that BP will eventually release more video and information so they can refine their estimates, what they have now is good enough. "It's possible to get a pretty decent number by looking at the video," Wereley said. This new, much larger number suggests that capturing — and cleaning up — this oil may be a much bigger challenge than anyone has let on. .

2 comments :

Brad Parsons said...

BTW, at 70,000 barrels a day, even 50,000 barrels a day, this spill equals the Exxon Valdez in less than 1 week. It has been flowing for 3 weeks. This spill is already worse than 3 times the Exxon Valdez.

Brad Parsons said...

BTW2, 70,000 barrels a day is 2,900,000 gallons a day of oil.

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