The team of BP investigators that probed what caused the blowout of its Macondo well insisted today that their inquiry was not designed to shield the London-based oil giant from blame.
“We were not about proportioning or apportioning fault or blame,” said Mark Bly, the BP safety chief who led the investigation.
“We understand our work may be used for those reasons,” Bly said, but that wasn’t the driving factor.
Bly insisted that the probe was conducted independently, without interference from BP officials who could be subject to criminal prosecution for their role in the Deepwater Horizon disaster.
“It was a very independent process,” with the investigative team using its own workspace and enjoying “complete license” to craft the inquiry “as we saw fit” and “bring in third-party expertise in the ways we saw appropriate,” Bly said. Ultimately, he said, the report straightforwardly describes “what we think went wrong, with no sort of differentiation between BP and the other companies involved.”
“We’ve been critical of ourselves as well as others,” Bly said.
Bly’s comments — delivered during a three-hour briefing for reporters in Washington, D.C. — rejected allegations by other companies involved in the drilling of BP’s doomed Macondo well. A spokesman for Transocean, the owner and operator of the Deepwater Horizon rig, today called the BP report “self-serving.” Lawyers, lawmakers and analysts said it was no surprise the report shifted blame away from BP and toward its partners on the project.
The BP investigators stressed eight problems and failures that may have culminated with the April 20 rig explosion that left 11 workers dead and triggered the nation’s worst offshore oil spill. But they repeatedly honed in on the failure of the cement job at the site, a focus that shifts attention to the work done by the cement contractor Halliburton.
In particular, the team faulted Halliburton for not doing what they characterized as adequate testing of the specific cement slurry used at the well.
The nitrogen-injected foam cement that was used at the site is susceptible to breaking down over time, especially if it is contaminated, noted BP’s Kent Corser.
BP was unable to get permission — both from Halliburton and because of a court order — to test the actual cement mix used at the Macondo well. However, they hired an independent lab, CSI Technologies, to run tests of a representative sample.
During a test of those samples in Houston, there was a significant loss in volume of the foam cement mixture, which BP officials said indicates that it may not have been stable when applied at the Macondo well — lending support to the idea that the cement foam may have broken down, shrinking and leaving vulnerabilities. Additionally, the company said the slurry may have been too thin when applied.
The stability of the nitrogen-injected foam cement “should have gotten more scrutiny,” Bly said. “Our finding was that Halliburton should have done more extensive testing and done a better job signaling to BP” about possible problems,” Bly added. In turn, the BP team “should have done a better job” ensuring those tests took place.
Ultimately, though, the team said that a bad cement job, in and of itself, shouldn’t have caused the lethal escape of natural gas from the well. “I don’t think it’s correct to think about would the disaster have occurred (but) for any one of these things,” Bly said. “It’s not unheard of to have a cement job fail” and that “does not immediately translate into a problem like this.”
The investigators also faulted workers on the rig for not going through a formal risk assessment after the cementing, given some key changes in the process — including the decision to go with fewer centralizers than originally planned to help ensure correct application.
“We believed a more rigorous risk assessment should have been made,” Bly said. BP’s criticism, he said, is that given everything that came before, “there should have been a risk assessment.”
Because that risk assessment never took place, Bly said, no one decided to run a cement bond log that might have detected problems in cement above the float collar.
The BP team insisted that had the flow of hydrocarbons been caught early enough — before it got into the riser pipe and gas started flowing onto the Deepwater Horizon — rig workers may have been able to avert disaster. An annulus-sealing ram could have been closed before the pressure built too high, noted BP’s Steve Robinson.
“A fundamental to drilling well control is early detection of influx — and early action,” Bly noted. “That’s fundamental. If you close it in early, you have a much better chance of getting a seal” and closing the well.