US rig survivors recall gas cloud and deadly blast

Robert Bea, a University of California Berkeley engineering  professor, said on Saturday he obtained transcripts of  interviews from three rig workers familiar with the explosion,  including two who were in the rig’s crew quarters at the time.

The interviews were done as part of BP’s internal  investigation of the accident but had not been made public.

Swiss-based Transocean Ltd’s Deepwater Horizon rig, under  contract with BP, exploded and caught fire on April 20 while it  was putting the finishing touches on a well about a mile (1.6  km) beneath the ocean surface. It sank two days later.

The accident has triggered a huge oil spill posing an  environmental and economic disaster to the US Gulf Coast.

As rig workers and engineers on the deck of the rig were  finishing a delicate operation to cement the metal well casing  in place, something went horribly wrong.

According to the transcripts, a giant bubble of methane gas  rushed up the drill pipe and enveloped the deck of the drilling  platform in a cloud of highly flammable gas, followed by a  scalding flood of crude oil that spilled onto the drill deck  and ignited.

Nine workers on the drill deck were killed, along with two  others working in the nearby mud storage room, Bea said.

“Gas and oil rushed up the riser. There was little wind and  a gas cloud got all over the rig,” according to a transcript  from a rig worker recited by Bea in a telephone interview.

The drill deck itself is “intrinsically safe,” meaning it  is free of any sources that can cause a spark such as a spark  plug in a generator, Bea said.

But the methane flood that rushed up the drill pipe was so  immense it soon spread across the entire length of the massive  drilling platform, Bea said.

When the gas reached a room where mud used in well-drilling  was stored, sparks from engines running pumps there ignited the  gas cloud, according to the transcript.

“When the main inductions of the engines got a whiff (of  the gas) they ran away and exploded — blew them right off the  rig,” the transcript said. “This set everything on fire.”

In the living quarters next to the mud storage room,  off-duty crew and visiting BP officials were celebrating seven  years of accident-free operation of the rig, according to the  transcript. The explosion blew the walls off the crew quarters  and sent furniture and people flying.

The blast “took out all of the interior walls where  everyone was hanging out having — I am not making this up — a  party to celebrate seven years of accident-free work on this  rig,” the transcript said.

“The furniture and walls trapped some, broke some bones,  but they all managed to get in the lifeboats with assistance  from others,” the transcript said.

A BP executive confirmed yesterday that seven BP  employees had been on the rig, from young engineers to a vice  president for Gulf of Mexico drilling operations. All escaped  safely, said Doug Suttles, BP’s chief operating officer.

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