The blowout preventer designed to shut down the BP well in an emergency couldn't stop the gush of deep sea oil into the Gulf of Mexico because a damaged piece of drill pipe got in the way, according to a federal report released Wednesday.
In the first comprehensive analysis of why the supposedly "fail-safe" equipment didn't work as planned, investigators concluded that when the Deepwater Horizon rig crew lost control of the well, the force of rushing oil buckled a section of drill pipe, which became stuck in the blowout preventer. The device had been activated, but the mangled pipe made it impossible for shearing rams to close and plug the flow of oil.
"As the blind shear rams closed, a portion of the drill pipe cross section became trapped … preventing the blocks from fully closing and sealing," said the 551-page report by the forensic analysis firm Det Norske Veritas.
The company determined that the physical failure would have occurred regardless of how the blowout preventer was activated — whether by an automatic "deadman's switch" or using hydraulic signals sent from workers on the rig, which exploded April 20 and sank after the well blowout.
DNV began testing the device at a NASA facility in New Orleans in mid November, at the direction of the Coast Guard and Bureau of Ocean Energy Management, Regulation and Enforcement, which are jointly investigating the disaster.
The report adds to other conclusions about the oil spill, including a presidential commission's determination that the lethal well blowout was the culmination of a series of decisions that increased risk at the site. The report suggested actions taken by the Transocean rig crew during its attempts to control the well may have contributed to the piece of drill pipe getting trapped.
The report also cast fresh doubt on the effectiveness of blowout preventers and immediately renewed calls for a redesign of the devices, including proposals for redundant pipe-cutting rams and more powerful pistons to drive them.
"This is the first time in all of this that there has been a clear design flaw in the blowout preventer cited," said Philip Johnson, a University of Alabama civil engineering professor who did not take part in the analysis. "My reaction is, 'Holy smokes, every set of blind shear rams out there may have this problem.' "
DNV recommended the oil industry further study whether shear rams can "complete their intended function" and completely cut drill pipe, no matter where it is in the well hole. The firm said that those conclusions should be incorporated in the design of future blowout preventers and used to modify those already deployed.
The blowout preventer at the BP well was manufactured by Houston-based Cameron and carried on Transocean's Deepwater Horizon drilling rig. Cameron spokeswoman Rhonda Barnat said the blowout preventer "was designed and tested to industry standards and customer specifications." She added, "We continue to work with the industry to ensure safe operations."
Transocean said in a statement that the examination confirms the blowout preventer "was in proper operating condition and functioned as designed."
Jeff Spittel, an analyst with the Houston investment banking firm Madison-Williams, said he doesn't believe the findings will shift legal liability for the accident onto Cameron, because the device was owned and operated by Transocean. And an indemnification clause in Transocean's contract with BP also could shield the rig owner from responsibility.
David Pursell, head of macro research of Tudor Pickering Holt & Co., a Houston energy investment bank, said the report appears to be a positive for both BP and Transocean because it indicates the blowout preventer was operating properly — even if it ultimately failed.
"All the pieces seemed to have functioned," Pursell said. "It doesn't seem there were problems with poor maintenance or operation."
Officials for BP, which leased the drilling rig from Transocean, said the oil company was still reviewing the report but agreed with its "recommendation that additional testing should be completed to provide a more comprehensive view of why the BOP failed."
The Coast Guard and ocean energy bureau are set to examine the blowout preventer testing results during hearings the week of April 4 in New Orleans. The panel is scheduled to release a final report over the summer assigning blame for the disaster.
Ervin Gonzalez, a Miami lawyer who is one of the lead plaintiffs' lawyers in the federal litigation spawned by the spill, said BP was ultimately responsible for ensuring that equipment on the rig was adequate and properly maintained.
"They can't shake that off by blaming other parties," he said. "They should have known the equipment was insufficient to maintain well control. We shouldn't be finding this out now. They should have known this before."
Information from Hearst Newspapers, the Los Angeles Times and Associated Press was used in this report.