(Editor's note: This story was updated June 23, adding BP's response in 2nd and 12th paragraphs)
OGJ Senior Staff Writer
HOUSTON, June 22 -- Transocean Ltd., owner of the Deepwater Horizon semisubmersible drilling rig that exploded and sank following the Macondo well blowout on Apr. 20, 2010, said BP PLC used a poor well design and failed to properly confirm critical cement tests.
The incident killed 11 people on the semi and resulted in a massive oil spill in the Gulf of Mexico. BP, which operated the Macondo well, issued a statement saying, "The Transocean report fails to acknowledge the significance of Transocean's role in the event. On its face, it appears to be an advocacy piece...."
In releasing its investigation report on June 22, Transocean reaffirmed its earlier statements that the Deepwater Horizon blowout preventer was maintained properly. The BOP’s inability to seal stemmed from circumstances caused by the deepwater well blowout, the drilling contractor said.
“It was overcome by the extreme dynamic flow, the force of which pushed the drill pipe upward, washed, or eroded the drill pipe and other rubber and metal elements, and forced the drill pipe to bow within the BOP,” Transocean said. “This prevented the BOP from completely shearing the drill pipe and sealing the well.”
A US Presidential Commission has said the incident stemmed from a number of separate risk factors, oversights, and outright mistakes by multiple parties and a number of causes.
Many lawsuits remain pending regarding the spill. Earlier this year, a court-imposed deadline in a New Orleans federal court prompted a flurry of claims and counterclaims. BP filed litigation against Transocean and others providing equipment or services for the Macondo well (OGJ, May 2, 2011, p. 40).
BP previously reached a settlement with partner MOEX Offshore 2007 LLC and its affiliates, Mitsui Oil Exploration Co. Ltd. and MOEX USA Corp., which agreed to pay BP $1 billion toward the cleanup (OGJ, May 30, 2011, p. 24).
MOEX had a 10% stake in Macondo. A second settlement involved service company Weatherford International Inc., which agreed to pay BP $75 million toward spill-related costs.
BP executives say their legal experts continue working with other companies involved in the well, including Anadarko Petroleum Corp., Transocean, and Halliburton Co., regarding liability for spill expenses. Anadarko had 25% interest in the Macondo well. Halliburton was involved in cementing the well.
Transocean said it commissioned an internal investigation team of experts from relevant technical fields and specialists in accident investigation to review and analyze the accident.
Previously, Transocean asked the US Coast Guard to revise its draft report on a joint investigation by the USCG and the Bureau of Ocean Energy Management, Regulation, and Enforcement into the Deepwater Horizon semi explosion and fire (OGJ, June 20, 2011, p. 20).
On June 22, BP said, "The Transocean report must be viewed in the context of official investigation findings by the Presidential Commission and the US Coast Guard that the Deepwater Horizon accident was the result of multiple causes, involving multiple parties, including Transocean. Indeed, the US Coast Guard identified 'serious safety management system failures and a poor safety culture' at Transocean."
Contact Paula Dittrick at firstname.lastname@example.org.