BP thinks again about how to staunch the flow of oil after “top kill” fails

AFTER three days of trying, on May 29th BP gave up on its attempts to stanch the flow of oil from its leaking well in the Gulf of Mexico with a procedure known as “top kill”. The following day, a White House adviser described the spill as the worst in America’s history.

“Top kill” depended on the company pumping large amounts of drilling mud into the blowout preventer, a set of valves which sits on the sea floor at the top of the company’s MC252 well, which was drilled by the ill-fated rig Deepwater Horizon. The idea was to push the mud down the well faster than the pressure of the rising oil and gas could push it back out of the top of the blowout preventer, eventually filling the well with a great enough weight of mud to keep the oil pressed down. To help with this the company fired various sorts of detritus into the blowout preventer, in the hope that the bits of wire and rubber thus introduced would plug the leaks at the top of the preventer and thus help make sure the mud went down, not up. But even with these “junk shots” the company could not get the procedure to work. …