Before the massive blowout of BP's Macondo oil well in the Gulf of Mexico, tests showed that the cement Halliburton pumped down into the well could be unstable, according to a presidential commission studying the Deepwater Horizon spill.
Halliburton has previously said that tests showed that the cement would be stable. Here's a quick report from NPR's Jeff Brady:
The chief counsel for the National Oil Spill Commission says in a letter that test results last spring should have raised questions about the cement used to seal BP's well.
Halliburton was contracted by BP to cement the well. It blew out April 20, killing 11 workers and eventually releasing more than 4 million barrels of oil into the water.
BP has previously identified a faulty cement mix as a possible cause of the accident, but the company declined to comment on this latest development. A spokeswoman for Halliburton says the company is reviewing the commission's report.
You can read the letter, from Fred Bartlit, here. In it, he says that the commission asked Chevron to conduct its own tests of the cement mixture. But the engineers "were unable to generate stable foam cement in the laboratory using the materials provided by Halliburton and available design information regarding the slurry used at the Macondo well," Bartlit writes.
After that report, Bartlit says, the panel asked Halliburton to turn over all data from all tests it had run on the cement mixture. In this excerpt, Bartlit discusses that data:
The documents provided to us by Halliburton show, among other things, that its personnel conducted at least four foam stability tests relevant to the Macondo cement slurry. The first two tests were conducted in February 2010 using different well design parameters and a slightly different slurry recipe than was finally used. Both tests indicated that this foam slurry design was unstable.
Halliburton provided data from one of the two February tests to BP in an email dated March 8, 2010. The data appeared in a technical report along with other information. There is no indication that Halliburton highlighted to BP the significance of the foam stability data or that BP personnel raised any questions about it. There is no indication that Halliburton provided the data from the other February test to BP.
Still, Bartlit says, the commission should not jump to any concusions based on those findings.
Toward the end of his letter, he notes that although only one of the four tests showed that Halliburton's slurry design would be stable, "we want to emphasize that even if our concerns regarding the foam slurry design at Macondo are well founded, the story of the blowout does not turn solely on the quality of the Macondo cement job."
And in a final suggestion that there may be plenty of blame to go around, he adds that since cementing deepwater wells is an imperfect science, oil companies have developed tests to identify flawed cement jobs -- and solutions to fix them.
Here's how Bartlit closes his letter: "BP and/or Transocean personnel misinterpreted or chose not to conduct such tests at the Macondo well."