ON THE GULF OF MEXICO — BP embarked on an operation yesterday that could seal the biggest offshore oil leak in US history once and for all, forcing mud down the throat of its blown-out well in a tactic known variously as bullheading or a static kill.
The pressure in the well dropped quickly in the first 90 minutes of the procedure, a sign that everything was going as planned, well site leader Bobby Bolton said aboard the Q4000, the vessel being used to pump in the mud.
He said the work could be complete by last night or today, though BP said the effort could continue through tomorrow, and engineers won’t know for more than a week if it choked the well for good.
The 122 crew members on the Q4000 were excited about being part of what could be the final resolution to a drama that started with the April 20 explosion on the offshore drilling rig Deepwater Horizon, Captain Keith Schultz said.
“I’m a mariner and we lost mariners out here,’’ said Schultz, who is on his second 28-day tour of duty since the spill started. “I’m very confident we’ll be able to kill this well. It’s been one magical time trying to get this thing plugged.’’
A 75-ton cap placed on the well in July has been keeping the oil bottled up over the past three weeks, but that is considered only a temporary measure. BP and the Coast Guard want to plug up the hole more securely with a column of heavy drilling mud and cement.
The static kill involves slowly pumping mud down lines running from a ship to the top of the ruptured well a mile below. BP said that may be enough by itself to seal the well.
But retired Coast Guard Admiral Thad Allen, the government’s point man for the spill, made it clear that to be safe, the gusher will have to be plugged from two directions.
He said the 18,000-foot relief well that BP has been drilling over the past three months will be used later this month to execute a bottom kill, in which mud and cement will be injected into the bedrock 2 1/2 miles below the sea floor.
“There should be no ambiguity about that,’’ Allen said. “I’m the national incident commander and this is how this will be handled.’’
Over the past few months, with each failed attempt to stop the leak, the American public has learned some of the oil industry’s lingo, including top kill, which is similar to the static kill, top hat, and junk shot, an attempt to clog up the well with golf balls and rubber scraps.
Before the cap was lowered onto the well, an estimated 172 million gallons of crude flowed into the sea, unleashed by the April 20 explosion aboard the Deepwater Horizon that killed 11 workers.
BP won’t know for certain whether the static kill has succeeded until engineers can use the soon-to-be-completed relief well to check their work.
