A trapped piece of drill pipe prevented a fail-safe device from stopping last year’s massive BP oil spill in the Gulf of Mexico, a US government investigation has found.
Its report said the device, known as a blowout preventer, failed to work properly because the piece of drill pipe had kept its “blind shear rams” from sealing the well around the time of the April 20 explosion on the Deepwater Horizon oil rig off the coast of Louisiana.
The rams are components in blowout preventers that cut, or shear, through drill pipe and form a seal against well pressure.
The Norwegian firm hired by the government to test the blowout preventer said the way the drill pipe had been positioned within the well bore caused it to buckle and bow when the well lost control, impeding the rams.
Det Norske Veritas’s report does not assign blame to any one company but does find fault with the performance and design of the blowout preventer.
The device was made by Cameron and maintained by Transocean.
The firm made several recommendations for the industry in its report, including changing the design of blowout preventers.
The company’s tests also indicated that some components in the back-up control systems did not perform as intended.
It advised the industry to revise its procedures for periodic testing and verification of these back-up systems.
Blowout preventers sit at the wellhead of exploratory wells and are supposed to lock in place to prevent a spill in case of an explosion.
The 300-tonne device that was used with BP’s Macondo well was raised from the sea floor on September 4.
Representatives for Cameron and Transocean were among an army of interested parties that were allowed to monitor DNV’s examination of the device.
BP, the US Justice Department and lawyers for plaintiffs in lawsuits over the disaster also were allowed to monitor.
None of them was allowed to have any hands-on involvement.
The official testing ended earlier this month. BP has asked a federal judge for permission to conduct additional testing on its own.
Cameron has objected, saying that if further testing is done, a neutral third party should do it.
The investigation into what caused the explosion on the Deepwater Horizon rig and subsequent oil spill is being overseen by a joint US Coast Guard-Bureau of Ocean Energy Management Regulation and Enforcement panel.