Executives from BP PLC, Transocean Ltd. and Halliburton Co. began pointing fingers on Monday over who bears ultimate responsibility for the April 20 oil-rig explosion that took 11 lives and is spilling oil into the Gulf of Mexico. The question will loom large at a Senate hearing Tuesday that will hear from executives of the three companies.
BP, the well owner, blames the failure of a big set of valves on the sea floor, known as the blowout preventer, to halt the blowout once it started.
A different account comes from Halliburton, a contractor in the drilling. This account is corroborated to some extent by Transocean, as well as by two workers on the drilling rig, The Wall Street Journal has determined.
This account describes a failure to place a cement plug within the well. The plug is designed to prevent gas from escaping up the pipe to the surface.
Before such a plug is placed, the job of keeping underground gas from coming up the pipe is done by heavy drilling fluid inside the well, commonly known as "mud." The plug is normally put in before the mud is removed, but according to the account of Halliburton, Transocean and the two workers, in this case, that wasn't done—drilling mud was removed before a final cement plug was placed in the well.
It is not clear why such a decision would have been made. Rig owner Transocean says that BP, as owner of the well that was just being completed, made key decisions on how to proceed. BP declined to comment on this account of the drilling procedures.
Tim Probert, Halliburton's president of global business lines, plans to testify Tuesday that his company had finished an earlier step, cementing the casing, filling in the area between the pipe and the walls of the well; pressure tests showed the casing had been properly constructed, he will testify.