Pumping a barrel of mud a minute, then two, then five, then seven, BP on Tuesday finally began slowly strangling its blown-out well at the bottom of the Gulf of Mexico.
The company and the Obama administrations cautioned it would take another step and a week or more to officially pronounce the monstrous gusher dead, but a successful “hydrostatic kill” operation would drive one huge nail in the coffin.
Early on, the signs from a mile below the Gulf’s surface were encouraging. BP said it began the process, which injects a dense “drilling mud” tipping the scales at 13.2 pounds a gallon to muscle oil and gas back down its ancient reservoir, around 4 p.m. after what BP Vice President Kent Wells called some “textbook” tests.
The Associated Press reported that well site leader Bobby Bolton estimated the job — also known as “bullheading” in the industry’s macho-speak — could be done by day’s end.
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But Wells, in an earlier teleconference, and federal officials estimated it would take several days to assess whether the operations had permanently plugged a well that spewed nearly 5 million barrels of crude into the Gulf, a volume some 20 times larger than the nation’s previous largest offshore oil spill.
Both Thad Allen, the retired Coast Guard admiral who leads the federal response task force, and Robert Gibbs, President Barack Obama’s press secretary, stressed that there would be no declaring victory until BP completes a relief well and delivers a final “bottom kill.”
“And there should be no ambiguity about that,” Allen said. “I’m the national incident commander, and that’s the way this will end.”
Though a massive 75-ton “stacking cap” sealed the well in July, Allen said it remained unclear where the flow was coming from inside a well running some 2 1/2 miles below the sea floor. Bullheading can plug in the well’s inner casing, he said, but an internal rupture also might be allowing oil or gas up the annulus, the open space between the casing that normally carries oil and gas and the larger bore hole surrounding it.
Earlier in the week, Wells had suggested that the static kill alone might be enough to finish off the well.
But Allen, supported by a team of federal scientists led by Energy Secretary Steven Chu, have argued that the only assured permanent plug is for the relief well to penetrate the annulus and pump in more mud and cement.
“We need to go into the bottom to make sure we fill the annulus, the casing and any drill pipe there and then follow that with cement,” Allen said. “This thing won’t truly be sealed until those relief wells are done.”