New videos from deep underwater show more dramatic footage of oil and gas gushing from the broken blowout preventer on the floor of the Gulf of Mexico. Scientists are anxious to get their hands on this and other video in order to make a better estimate of the oil spill.
Sens. Bill Nelson (D-FL) and Barbara Boxer (D-CA) had asked BP for all its underwater spill videos; they got their first batch Tuesday.
Last week -- at NPR's request -- scientists analyzed a clip of video BP had released, and concluded that the spill is much bigger than the official estimates.
Estimating Size Of Spill
One major point of those stories was that scientists were saying it is quite possible to measure the size of the spill by studying videos of it. BP was saying it isn't possible to get an accurate answer by doing that.
Although the experts working with NPR are confident the April 20 spill is much bigger than the official estimate, there's still a lot of uncertainty in their figures.
Steven Wereley, an associate professor of mechanical engineering at Purdue University, and Timothy Crone, an associate research scientist at Columbia University's Lamont-Doherty Earth Observatory, were only studying one 30-second video clip -– a shot of the main spill, coming out of a 21-inch pipe. The new video shows other impressive streams of oil and gas coming out from around the blowout preventer 600 feet away.
Wereley concluded that the flow from the main pipe was 70,000 barrels a day, plus or minus 20 percent (one barrel is approximately 42 gallons). That's 14 times the official estimate. But he added an important caveat: It was not clear how much of the flow is oil and how much is natural gas.
Last week, a BP spokesman told NPR the company didn't know that ratio. Then on Sunday, another company official told NPR the gas-oil ratio is 3,000:1 -– that is, 3,000 cubic feet of gas per barrel of oil. That's at sea level. At the seafloor, where the pressure is high, the gas compresses a lot, but the oil doesn't. So scientists tell NPR, given BP's ratio, that would mean there's three times as much gas coming out of the leaking pipe as there is oil.
However, Wereley and Crone note there is still a great deal of oil visible coming out of the broken pipes. And they are standing by their original estimates as they prepare to make a closer study of the new videos.
Measuring A Spill
Even so, BP continues to use the official figure, which is about 5,000 barrels a day. That number is based on a federal survey, two weeks ago, of oil on the surface of the Gulf of Mexico. It is standard practice to measure an oil spill by gauging oil on the surface.
But Congress is now asking whether the standard practice is best. Wereley is slated to testify Wednesday at a congressional hearing looking into methods for measuring spilled oil.
One question is why all this matters. The federal government and BP say they are already treating the spill as a major catastrophe, and there is really nothing more they can bring to bear.
But there may be legal reasons to care. Eventually, BP will be subject to the federal Oil Pollution Act, which will hold them responsible for damages to people as well as to the environment. It will be difficult to assess the environmental damage from this spill, so legal scholars expect that eventually BP's financial responsibility could be tied to the amount of oil spilled.
In addition, knowing the volume of oil could be important to scientists who are trying to track the movement of oil. And, of course, BP's own engineers working on ways to stop the spill would want to know how much oil and gas are coming out of the breaches -– and at what velocity.