Hot off the wires from the Associated Press, the cause of the Deepwater Horizon explosion is believed to have been found:
The deadly blowout of an oil rig in the Gulf of Mexico was triggered by a bubble of methane gas that escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding, according to interviews with rig workers conducted during BP's internal investigation.
But the really astonishing part of this story is what was happening on the rig at that very moment...
A group of BP executives were on board the Deepwater Horizon rig celebrating the project's safety record, according to the transcripts. Meanwhile, far below, the rig was being converted from an exploration well to a production well.
[I have added some further unflattering details at the bottom.]
This is certainly an interesting wrinkle to the story, and I'm not surprised it hasn't come out before now. BP already has a (well deserved) public relations nightmare on its hands, and the news that their execs were in the process of toasting their own safety record at the very moment of the catastrophe is not likely to make things much better.
As mentioned in the opening paragraph, this all comes from an internal investigation conducted by BP, and represents the conclusions of Robert Bea, a University of California Berkeley engineering professor:
Based on the interviews, Bea believes that the workers set and then tested a cement seal at the bottom of the well. Then they reduced the pressure in the drill column and attempted to set a second seal below the sea floor. A chemical reaction caused by the setting cement created heat and a gas bubble which destroyed the seal.
Bea describes a horrifying scenario:
As the bubble rose up the drill column from the high-pressure environs of the deep to the less pressurized shallows, it intensified and grew, breaking through various safety barriers, Bea said.
"A small bubble becomes a really big bubble," Bea said. "So the expanding bubble becomes like a cannon shooting the gas into your face."
This is what those rig workers had to deal with:
"What we had learned when I worked as a drill rig laborer was swoosh, boom, run," Bea said. "The swoosh is the gas, boom is the explosion and run is what you better be doing."
The gas flooded into an adjoining room with exposed ignition sources, he said.
Scary stuff, and sheds some new light on what those workers must have gone through. But the revelation of the unfortunately timed celebration by the head honchos is what really strikes me. Along with their calloused offering of chump change to Gulf Coast residents, this will likely not reflect well on their image.
The men were kept aboard the rescue ship, in the middle of the ocean, for a full 12 hours. Worse than the wait, they said, was being forbidden to call their families. The men were told that the Coast Guard wanted to conduct interviews before the workers spoke to family or anyone else.
Rumors spread that the BP executives who had visited the rig were up on the [rescue ship's] bridge using the ship’s radio or a satellite phone to call home.
[Once off the rescue ship] Behind the table was a row of portable toilets. And as the crew members approached, each was handed a cup for a mandatory drug test. The search for an explanation would begin with them. That search continues.