Oil Flow May Be Much Worse Than Original Estimate

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The Coast Guard has estimated the flow of oil into the Gulf of Mexico at 5,000 barrels a day. But a scientist analyzing a newly released video of the leak says it's at least 10 times that amount. That means the oil spilling into the Gulf has already far exceeded the amount lost in the Exxon Valdez accident. NPR science correspondent Richard Harris talks to Michele Norris about the new estimate.


From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.


And I'm Michele Norris.

Oil giant BP says it will soon attempt two new fixes to stop the oil leaking into the Gulf of Mexico. Tonight, crews hope to insert a tube into the leaking pipe to siphon oil before it hits the water. Also standing by on the seafloor is what they call a top hat, which would cover the leaking pipe. In a moment we'll hear from anxious residents in Louisiana.

But first, the blowout in the Gulf of Mexico appears to be releasing far more oil into the water than we've been hearing. The Coast Guard estimates the flow at 5,000 barrels a day. But a scientist using sophisticated techniques to analyze a newly released video of the leak says it's at least 10 times that amount. That would mean the oil spilling into the gulf has already far exceeded the amount lost in the Exxon Valdez accident.

Joining us to talk about this is NPR's science correspondent Richard Harris. And, Richard, explain where this new estimate came from.

RICHARD HARRIS: Well, yesterday, BP released a short video clip of the oil gushing out of the pipe on the seafloor. And today I asked several scientists who know how to interpret videos to take a close look at that and tell me what they think.

Now, the most sophisticated method they use is called PIV, particle image velocimetry, which is a very well-established method to measure the speed of fluids. And Professor Steve Werely at Purdue University put the BP video into his computer program and concluded that the oil is spilling out at a rate of 70,000 barrels a day. That's more than 10 times higher than the guesstimate that the Coast Guard has been using.

NORRIS: And how certain is Professor Werely of that figure?

HARRIS: Well, he says his method is accurate to about 20 percent, plus or minus, which means it could be maybe as little as 56,000 barrels a day or maybe as much as 84,000 barrels a day.

It's also true, though, that the pipe is spewing out both oil and gas. And from the short video clip that BP released, it's not clear how much of the volume is oil and how much is gas. So the total for oil alone will be less. But based on just that short video clip, we can't really say how much less.

NORRIS: And is it possible to confirm the estimate?

HARRIS: Well, I also talked to an astrophysicist at U.C. Berkeley named Eugene Chiang who used a much simpler method to make an estimate. And he says the flow is in a range of 20,000 to 100,000 barrels a day, obviously, a lot of uncertainty there. But clearly, he says, it's not as little as 5,000 barrels a day, which is the official number right now.

NORRIS: Richard, we noted that the amount of oil that has spilled into the gulf has already exceeded the amount lost in the Exxon Valdez accident by how much, any idea?

HARRIS: Well the Exxon Valdez accident in Alaska put about 250,000 barrels of oil went into the Alaskan water. So, assuming the plume is mostly oil and not gas, it looks like the blowout in the gulf has already eclipsed that figure. In fact, it probably eclipsed the Exxon Valdez in the first week. And now, we're into, what, the third of the disaster.

NORRIS: Mm-hmm. What are the possible implications of this?

HARRIS: Well, we already know that there's an enormous amount of oil slick in the gulf. I mean clean-up efforts focus on the oil they can see on the surface, and this number doesn't change the amount of oil they see on the surface clearly. So, in that regard, it doesn't make that much difference.

But it could make a difference at the wellhead. BP does want to have a pretty good idea. They should want to know how much oil they're dealing with as they fight this problem at the bottom of the sea. And, of course, it's really about good P.R. to have a spill that it seems will end up being much larger than the iconic Exxon Valdez spill.

NORRIS: What does BP have to say about this?

HARRIS: Well, BP has always said that there is no way to measure the amount of oil spilling out of the broken pipe at the bottom of the sea. And they reiterated that comment to me last night. And they said that view is shared by people in the Coast Guard and in other federal agencies.

Well, clearly, folks in academia disagree. They have well-established methods that they can do that. They can do it quickly and with reasonable precision. And they say - they say they can actually do a much better job if they had more video and more information from BP. So there is uncertainty here, but the uncertainty could be reduced if BP would share more information with the scientists.

NORRIS: Mm-hmm. Richard, thank you very much.

HARRIS: My pleasure.

NORRIS: That's NPR's Richard Harris.

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