This morning, officials raised their estimate of the amount of oil spilling out from the destroyed Deepwater Horizon rig in the Gulf of Mexico from 1000 to 5000 barrels per day. But how much oil will ultimately reach the shore of the gulf is only one of the questions that officials now face.
Oil companies have been drilling in ocean depths of approximately 1525 meters for more than a decade, but there's never before been an accident like the one that occurred on 20 April. The essential problem was a so-called "blowout"—an explosive release triggered when the oil and gas under high pressure in the well beneath the surface exceeds the pressure of the machinery trying to tap it. In this case, the gusher caused a deadly fire (now extinguished) and a continuous oil spill that is spreading over the surface of the ocean toward the Louisiana coast.
There's a ton of speculation as to why the original accident occurred when it did, (some helpful guesses on that). Experts say they just don't know for sure. But an even more important question is why a series of valves in the 450-ton "blowout preventer" (BOP) failed to close off the gusher after it began. The BOP, which sits on the sea floor, can close off any gushing well in several ways—such as by plugging a pipe or even by crushing it horizontally like squeezing a straw until it is cut off. A key piece of machinery, the BOP is usually tested regularly, even daily.
"The industry and academia are continuously improving the technology, and even though an accident like this is extraordinarily rare, we cannot let this happen again," says Paul Bommer, a professor of petroleum engineering at the University of Texas, Austin. One of the first tasks will be to investigate why none of the four ways to activate the BOP has worked.