Deepwater Horizon blowout: 60 Minutes

On CBS "60 Minutes" last night, an exclusive interview with Deepwater Horizon survivor Mike Williams revealed three possible causes of the catastrophic oil rig explosion on April 20th:

First:

Down near the seabed is the blowout preventer, or BOP. It's used to seal the well shut in order to test the pressure and integrity of the well, and, in case of a blowout, it's the crew's only hope. A key component is a rubber gasket at the top called an "annular," which can close tightly around the drill pipe.

Williams says, during a test, they closed the gasket. But while it was shut tight, a crewman on deck accidentally nudged a joystick, applying hundreds of thousands of pounds of force, and moving 15 feet of drill pipe through the closed blowout preventer. Later, a man monitoring drilling fluid rising to the top made a troubling find.

"He discovered chunks of rubber in the drilling fluid. He thought it was important enough to gather this double handful of chunks of rubber and bring them into the driller shack. I recall asking the supervisor if this was out of the ordinary. And he says, 'Oh, it's no big deal.' And I thought, 'How can it be not a big deal? There's chunks of our seal is now missing,'" Williams told Pelley. [snip)

Second:

The BOP is operated from the surface by wires connected to two control pods; one is a back-up. Williams says one pod lost some of its function weeks before.

Transocean tells us the BOP was tested by remote control after these incidents and passed. But nearly a mile below, there was no way to know how much damage there was or whether the pod was unreliable.

 Third:

In finishing the well, the plan was to have a subcontractor, Halliburton, place three concrete plugs, like corks, in the column. The Transocean manager wanted to do this with the column full of heavy drilling fluid - what drillers call "mud" - to keep the pressure down below contained. But the BP manager wanted to begin to remove the "mud" before the last plug was set. That would reduce the pressure controlling the well before the plugs were finished.

Asked why BP would do that, Bea (Dr. Bob Bea, a professor of engineering at the University of California, Berkeley) told Pelley, "It expedites the subsequent steps."

"It's a matter of going faster," Pelley remarked.

"Faster, sure," Bea replied.

Bea said BP had won that argument.

"If the 'mud' had been left in the column, would there have been a blowout?" Pelley asked.

"It doesn't look like it," Bea replied.

Stay tuned.