Halliburton cement at fault for BP spill?

WASHINGTON, Oct. 29 (UPI) -- Halliburton and BP knew weeks ahead of the Gulf of Mexico oil spill that the cement mixture used to seal the Macondo well was unstable but didn't act on the information, says a report by a presidential commission.

The April 20 explosion killed 11 workers and caused the largest offshore oil spill in American history. Halliburton served as a contractor to BP and was responsible for cementing the well.

In a letter to the commission Thursday, the lead investigator, Fred Bartlit, said that the cement mixture used on the well didn't meet industry standards and failed three out of four laboratory tests before the explosion.

"Halliburton (and perhaps BP) should have considered redesigning the foam slurry," Bartlit's letter said.

Robert Bea, a professor and oil industry expert at the University of California at Berkeley told The Washington Post that drillers will often run one test on a cement mixture, then a second test as a backup. He noted that four tests are "unusual."

"Given that they are running four, that's telling me they were having trouble getting to a stable design," Bea said. "And so they continued to work with this witches' brew until they got on to something they thought was workable."

In a statement issued Thursday in response to the commission letter, Halliburton said it didn't believe that cement issues were the cause of the well rupture.

"Halliburton believes that significant differences between its internal cement tests and the commission's test results may be due to differences in the cement materials tested," the statement said. "The commission tested off-the-shelf cement and additives, whereas Halliburton tested the unique blend of cement and additives that existed on the rig at the time Halliburton's tests were conducted."

The statement continued: "Halliburton believes that had BP conducted a cement bond log test, or had BP and others properly interpreted a negative pressure test, these tests would have revealed any problems with Halliburton's cement."

Halliburton has publicly stated that it tested the Macondo cement before pumping it on April 19 and 20 and that its tests indicated the cement would be stable.

Halliburton also supplied the material used in the Montara well off the coast of Australia that blew out in August 2009, The New York Times said.

"The fact that BP and Halliburton knew this cement job could fail only solidifies their liability and responsibility for this disaster," U.S. Rep. Edward J. Markey, D-Mass., chairman of the House Energy and Environment Subcommittee Markey said in a statement.