Halliburton Defends Its Cement Job on BP's Well

(Oct. 29) -- Halliburton Co. conceded today it did not test the stability of the final cement mixture used to seal BP's Macondo well, but it disputed an assertion by the presidential commission that the cement gave way and set off a sequence of events that caused the catastrophic blowout in the Gulf of Mexico.

"Halliburton does not believe that the foam cement design used on the Macondo well was the cause of the incident," the company said in a four-page statement.

The stability of the cement mixture has long been suspected as one of the possible factors that led to the blowout, which killed 11 workers on the Deepwater Horizon rig and spewed more than 5 million barrels of oil into the gulf.

On Thursday, scrutiny of the quality of the cement work intensified when the Oil Spill Commission revealed that Halliburton, the cement contractor, and BP knew the cement mixture was unstable but used it anyway.

New details about four tests performed on the cement mixture in February and April were revealed in a letter to the panel from its chief investigator, Fred Bartlit Jr. Only the last of the four tests, performed a week before the blowout, showed the mixture was stable, Bartlit found.

In its statement, Halliburton disputed some of those findings and provided other details of the cement testing.

Throughout the testing period, Halliburton adjusted the cement mixture formula, a common industry practice. After the last test found the mix to be stable, BP ordered that the formula be changed again, Halliburton said. BP wanted to increase "the amount of retarder in the slurry formulation from eight gallons per 100 sacks of cement to nine gallons per 100 sacks of cement."

The changed formula was tested again before it was pumped into the well on the evening of April 19, the night before the blowout. The tests of the thickening time and compressive strength were performed. Yet a crucial foam stability test was not conducted, Halliburton said.

Halliburton has blamed BP's well design for the blowout from almost the start of the investigation. In its response to the oil spill panel's revelations, the company also faulted BP for failing to take several steps that could have uncovered any deficiencies earlier enough for them to be corrected, possibly preventing the blowout from occurring.

Among its lapses, Halliburton said, was BP's failure to perform a critical cement bond log test that would have revealed any flaws in the cement.

"A cement bond log test is the only means available to evaluate the integrity of the cement bond," Halliburton said. "BP, as the well owner and operator, decided not to run a cement bond log test even through the appropriate personnel and equipment were on the rig and available to run that test."

Halliburton also said negative pressure tests, also developed to identify failures in cement work, were misinterpreted by BP and Transocean workers on the rig.

"Halliburton believes that had BP conducted a cement bond log test or had BP and others properly interpreted the negative-pressure test, these test would have revealed any problems with Halliburton's cement," the company said.

BP spokesman Daren Beaudo declined to comment on either the panel's finding or Halliburton's statement.

In August, Jesse Gagliano, a technical adviser for Halliburton, testified before the joint Coast Guard-Interior Department inquiry into the accident that he had warned BP that its well design increased the risk of gas leaks. Gagliano testified that he told BP five days before the blowout that its plan to use just six centralizers to secure the well instead of 21 would increase the risks.
The devices are used to secure the steel lining of the well with cement.

In its statement, Halliburton said BP "made the decision to use only six," even though an additional 15 centralizers had been sent to the rig.

"Halliburton predicted that the cement job would channel (or weaken) and provide a flow path for hydrocarbons," the oil services giant said.

Halliburton also questioned the commission's methodology in independently testing the quality of Halliburton's cement mixture. The panel hired cement experts at Chevron in Houston to test the mix. But Halliburton noted Chevron used "off-the-shelf cement and additives" that differed from the "unique blend of cement and additives that existed on the rig at the time."

"Halliburton believes that significant differences between its internal cement tests and the Commission's test results may be due to differences in cement materials tested," the company said.

The company did not supply the panel with that mixture and suggested it had been a court order in connection with the Justice Department civil and criminal investigation had prevented anyone from gaining access to the recipe. Halliburton said it will release the materials "soon" to the Coast Guard-Interior Department investigators.