BP releases report on gulf well blowout

By Steven Mufson and Joel Achenbach
Wednesday, September 8, 2010; 6:02 PM

BP released a long-awaited report Wednesday on an internal investigation into the causes of its Gulf of Mexico oil well blowout, blaming multiple failures by BP and other firms but absolving its much-criticized well design.

The BP report stressed that "no single factor" caused the April 20 blowout that killed 11 workers, sank the Deepwater Horizon drilling rig and led to the largest oil spill in U.S. history.

Instead, with lawsuits and a Justice Department criminal investigation in progress, BP spread the blame widely, declaring the disaster a "shared responsibility."

In a news briefing after the report was released, investigation leader Mark Bly, BP's head of safety and operations, was asked whether BP sacrificed safety to save money, as other investigators have alleged. Bly replied that his team did not find anything to support that conclusion.

The report brought a sharp rebuke from one leading congressman, Rep. Edward J. Markey (D-Mass.), a member of the House Energy and Commerce Committee.

"Just as the environmental damage did not end with the capping of BP's well, this company-run investigation is not the end of the inquiries into the BP oil spill," he said in a statement. "This report is not BP's mea culpa. Of their own eight key findings, they only explicitly take responsibility for half of one. BP is happy to slice up blame, as long as they get the smallest piece."

The report on BP's four-month investigation by a team of more than 50 technical and other specialists said that "multiple companies and work teams" made decisions that contributed to the oil spill.

It cited the failure of the type of cement slurry that was used, along with a mechanical valve known as a shoe that is designed to let fluids flow only in one direction.

The report also said that BP and Transocean workers "incorrectly accepted" the results of a pressure test. And it added that over a crucial 40-minute period, the Transocean rig crew "failed to recognize and act on the influx of hydrocarbons into the well" when it might still have been possible to cut off the flow.

In addition, the report pointed to failures after that point. It said that the gas that surged to the rig should have been diverted overboard but was vented directly onto the rig and then through its ventilation system.

"It is evident that a series of complex events, rather than a single mistake or failure, led to the tragedy," said outgoing BP chief executive Tony Hayward, who has agreed to step down Oct. 1. "Multiple parties, including BP, Halliburton and Transocean, were involved."

He added: "Based on the report, it would appear unlikely that the well design contributed to the incident, as the investigation found that the hydrocarbons flowed up the production casing through the bottom of the well."

Other oil company executives have said BP used a well design that was cheaper and easier to implement instead of a safer but more expensive design.

In a statement, Transocean said BP's "self-serving report" attempts to conceal the "fatally flawed well design" that set the stage for the gulf incident. "In both its design and construction, BP made a series of cost-saving decisions that increased risk - in some cases, severely," Transocean said.

BP's investigative team "did not identify any single action or inaction that caused this accident," the company said. "Rather, a complex and interlinked series of mechanical failures, human judgments, engineering design, operational implementation and team interfaces came together to allow the initiation and escalation of the accident. Multiple companies, work teams and circumstances were involved over time."

BP said that even after the multiple failures it cited, the blowout preventer on the sea floor should have activated automatically to seal the well. But it said the device "failed to operate, probably because critical components were not working."

The blowout preventer was brought to the surface on Friday and is in the custody of government investigators.

The team that wrote the report made 25 recommendations to prevent such accidents in the future.

"We have said from the beginning that the explosion on the Deepwater Horizon was a shared responsibility among many entities," BP's incoming chief executive, Bob Dudley, said in a news release. "This report makes that conclusion even clearer, presenting a detailed analysis of the facts and recommendations for improvement both for BP and the other parties involved."

Dudley said that BP was looking at how to implement the recommendations in its drilling operations worldwide.

In its report, BP identified four major categories of failures that led to the disaster. The well lost "integrity;" hydrocarbons entered the well, undetected at first; gas flowed onto the rig and ignited; and the blowout preventer failed to seal the well, it said.

"If any of the critical factors had been eliminated, the outcome of Deepwater Horizon events on April 20, 2010, could have been either prevented or reduced in severity," the report said.

In spreading the blame widely, BP's investigators did not spare the on-shore employees. For example, it said, "the BP Macondo well team," which included Houston-based engineers, "did not provide effective quality assurance on Halliburton's technical services."

The report also implicated the "spacer" fluid used in the process of displacing mud from the riser and replacing it with sea water. A "mud" engineer testified this summer at a federal inquiry that he combined two chemically different batches of spacer fluid and sent them both down the well during the mud displacement procedure.

The decision to send an unusually large amount of spacer fluid down the well was apparently motivated by an exemption in Environmental Protection Agency rules stating that certain fluids used in a well can be dumped directly into the Gulf of Mexico rather than shipped at great expense to a hazardous waste facility on land.

The report said the presence of the spacer across the inlet to a pipe called the kill line "could have complicated the interpretation of the negative-pressure test."

The chemicals used in the spacer were intended for a different purpose - gumming up gaps in the rock formation. The material could have plugged the "kill line" during the pivotal pressure test, the report said.

The BP report said some of the company's most heavily scrutinized decisions -- choices other investigators have said saved money at the expense of safety -- did not contribute to the disaster.

BP used only six devices called centralizers instead of the 21 recommended by contractor Halliburton to center the pipe in the well. In addition, at a savings of millions of dollars, it installed a type of steel casing toward the bottom of the exploration well that could be used again when the well entered the production phase.

The internal investigators do not believe either decision was "causal," said Kent Corser, a member of the investigating team.

Before the report was issued, BP executives said for months that it was too soon to say why the rig exploded. The new report comes as other investigations continue, including the Justice Department criminal probe.

The internal inquiry began just days after the blowout, as BP investigators questioned the well site leaders, Donald Vidrine and Robert Kaluza, the "company men" who were on board the rig at the time of the explosion. Neither has testified publicly or given interviews.

The investigation also probed the design of the well, the maintenance of the blowout preventer that failed to choke the well at the crucial moments, and the decision by BP executives to proceed with a cement job despite a report by the contractor, Halliburton, stating that the well as designed was potentially subject to a "severe" gas flow problem.

Before the new BP report, the general outline of what happened had been clear for months. The exploratory well, named Macondo by BP, had been a difficult drilling job in 5,000 feet of water in the Gulf of Mexico. The Deepwater Horizon, owned by Transocean and leased by BP, was weeks overdue for its next drilling assignment. The blowout took place in the final stages of the plugging and temporary abandonment of Macondo. Federal investigators have probed whether the company took short cuts or made safety-related decisions with cost in mind.

Halliburton employees had cemented the well, but BP did not choose to run a "cement bond log" test that might have detected whether there were fissures in the cement that could have given gas an avenue to the surface.

Then, on the afternoon of April 20, BP ran two pressure tests that, in retrospect, clearly signaled that gas was flowing in the well and that BP had a serious well-control problem on its hands. But rather than shutting in the well at that point, the leaders on the rig interpreted the tests as benign. They continued to remove heavy drilling mud from the well and replace it with much lighter sea water. That's when the blowout happened.

The other companies involved have yet to give their version of events, and Transocean has pointedly complained that BP hasn't turned over data that would help Transocean with its own internal investigation.

Staff writers William Branigin and David Hilzenrath contributed to this report.

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