Thursday, September 9, 2010

"We have a situation," the assistant driller said. "The well is blown out.”

The Associated Press has a riveting account of the doomed Deepwater Horizon rig’s last hours.  Three days before the fateful blowout, explosions and fire that killed 11 men, sunk the rig and set off the nation’s worst marine oil spill, senior Halliburton technical adviser Jesse Gagliano warned colleagues that “we have a potential problem here:”

Gulf Oil Spill Investigation "We have a potential problem here," the Halliburton employee told 3 colleagues he met in the hallway in BP PLC's Houston headquarters. He said his computer model was predicting a "serious gas flow problem" with BP's well abandonment plan.

His idea for addressing the issue would never be carried out. BP decided it wasn't necessary. Five days later, on April 20, the well blew out, causing the worst offshore oil spill in U.S. history.

In an internal report released Wednesday, BP stood by its decision, saying Gagliano's plan would not have stopped the explosion.

The disagreement was just one of several that emerged in the days and hours before the blast, according to BP's report and e-mails, documents and testimony gathered by federal investigators. Confusion surrounded crucial tasks and frustration rose among people involved.

BP operated the well, Transocean owned the rig and Halliburton carried out the cement job. They had to work together.  Yet key plans kept changing. Critical tests meant to ensure the well would be safely cemented were not going smoothly.

Gagliano's computer model exposed yet another possible problem. The longtime technical adviser concluded that the cementing operation needed more centralizers, devices designed to ensure that the casing — or drilling pipe — runs down the center of the wellbore to increase the chance for a perfect seal and prevent leaks. BP had planned to run six centralizers and had them onboard.

After a corridor chat with BP's senior drilling engineer, Gagliano worked up more models. By the evening of April 15, Gagliano had a model with 21 centralizers that resolved the gas flow problem. The 15 additional centralizers were acquired and scheduled for delivery the next morning, in time for the Halliburton cementers to do the job.

BP drilling engineer Brett Cocales learned the next afternoon, April 16, that his company's engineers had decided against using the additional centralizers because of questions about their mechanical integrity. Members of a BP investigation panel said Wednesday that those concerns were unfounded because engineers were mistaken about which centralizers had been shipped.

In an e-mail to fellow drilling engineer Brian Morel, Cocales explained the extra centralizers could help meet the goal of inserting the casing properly. Then he continued:

"But who cares? It's done. We'll probably get a good cement job," he wrote, frustrated it had taken so long to make a decision.

Obviously, they didn’t get a good cement job at all, because four days after Cocales’ and Morel’s email exchange, a methane gas bubble erupted through the well, displacing mud and seawater on its way through the crown of the Deepwater Horizon.  A series of mistakes aboard the well then let the gas escape and reach an ignition source.

By all means, go read AP correspondent Ramit Plushnick-Masti’s account of the events, conversations and people involved.

But as I pointed out here yesterday, this is an account of a chain of events in which had someone made the right choice at any point in the process, the disaster would have likely been averted or the blowout brought under control. Instead, the rig was doomed by a cascading series of missteps, from failing to insure that a “fool proof blowout preventer” was indeed foolproof during testing; failing to heed Gagliano’s advice on centralizers; Vidrine’s decision to displace the mud with seawater; the crew’s failure to implement emergency procedures once they realized that the well was gonna go.

A tragic series of events indeed, but a series of events that is exceedingly rare in today’s oil and gas exploration industry.