BP's report last week on findings of an investigation into the fatal Macondo well blowout is a landmark event that will require months if not years for the oil and gas producing industry fully to digest. It documented a complex sequence of lapses that will influence regulation, lawsuits, industry practice, politics, and personal lives for even longer.
For all its complexity and ramification, the report proved remarkably suited to summarization. The chore fell to Tony Hayward, outgoing BP chief executive. "There was a bad cement job and a failure of the shoe track barrier at the bottom of the well, which let hydrocarbons from the reservoir into the production casing," Hayward said in a press statement. "The negative pressure test was accepted when it should not have been, there were failures in well-control procedures and in the blowout preventer, and the rig's fire and gas system did not prevent ignition."
Hayward would not make this type of statement in his appearance on June 17 before the House Committee on Energy and Commerce. He drew bipartisan scorn for repeatedly deferring to the BP investigation then under way, insisting that statements about causes of the blowout would be only speculation. He pointedly refused to address five decisions the committee criticized in a letter 3 days before he testified. The committee identified the decisions from testimony and its own investigations.
While the BP report didn't respond point by point, comparison of the committee allegations with findings of the BP probe helps bring events leading to the tragedy into focus.
• Well design. In the Macondo well, BP installed a full string of casing. The committee pointed out that a liner and tieback would have provided more barriers to annular flow. The BP study concluded that fluid encroachment occurred through the casing rather than the annulus and that the casing retained its integrity.
• Centralizers. Although models recommended installation of 21 centralizers for cementing of the production casing, BP used 6 and declined to install 15 units flown to the well. Maintaining a theme of its critique, the House committee suggested the decision reflected excess haste and concern for cost. The BP report said decision-makers on the rig mistakenly thought they had received the wrong centralizers and feared they might fail. It said use of fewer than the recommended number of centralizers might have raised risks of cement problems above the main hydrocarbon zone but probably didn't contribute to the cement problems that actually occurred.
• Cement bond log. The committee faulted BP for not running a normal evaluation of the casing cement job. The study acknowledged that, contrary to company guidelines, no such evaluation was run.
• Mud circulation. The committee said BP didn't circulate enough mud to adequately perform the "bottoms-up" procedure normally conducted before cementing. The BP report said the crew circulated about six times the open-hole volume but limited the procedure over concerns about losses and hole washout.
• Lockdown sleeve. The committee faulted BP for not installing a casing-hanger lockdown sleeve to keep the seal from being blown out from below. The BP report said installation of a sealing device would have occurred before well completion. Because the main escape route for reservoir fluids was the production casing rather than the annulus, the seal wasn't a factor in the blowout unless it failed under thermal stresses after catastrophic flow was under way.
So both bodies saw problems with cement: the committee with procedure and BP more with formulation. Both noted failure to evaluate the cement job. BP reported errors of test-result interpretations, well-control and fire responses, and BOP operation on which the committee, in its letter to Hayward, was silent.
The differences are interesting but at this point only that. They serve mainly to help plug the intellectual gaps with which Hayward, perhaps wisely, left a panel of angry lawmakers.
And they bring a beleaguered industry no closer than it has been since Apr. 20 to the answer to a crucial question: Why?
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