Federal probe: Cement problems, other failures triggered Deepwater Horizon disaster

A series of failures at BP’s doomed Macondo well culminated in the lethal Deepwater Horizon disaster and last year’s Gulf oil spill, federal investigators concluded today.

The findings by the Coast Guard and the Bureau of Ocean Energy Management, Regulation and Enforcement dovetail with the conclusions of other oil spill probes, by highlighting a series of fatal mistakes that led to the April 20, 2010 blowout at BP’s well and the lethal blast on Transocean’s Deepwater Horizon rig.

The group concluded:

“The loss of life at the Macondo site . . . and the subsequent pollution of the Gulf of Mexico through the summer of 2010 were the result of poor risk management, last minute changes to plans, failure to observe and respond to critical indicators, inadequate well control response and insufficient emergency bridge response training by companies and individuals responsible for drilling at the Macondo well and for the operation of the Deepwater Horizon.”

The 217-page document released today is viewed as the most significant and comprehensive account of what went wrong at the site. The report will provide the foundation for new requirements for offshore wells and the emergency equipment that guards them.

The report’s findings also will provide fodder for oil spill lawsuits and have legal implications for the three companies whose work was central at the site: BP, which owned and designed the well; Transocean, which owned and operated the Deepwater Horizon rig; and Halliburton Co., which performed cementing at the site.

The Coast Guard and ocean energy bureau investigators conclude that BP, Transocean and Halliburton violated more than a half dozen federal offshore safety regulations in their work at the site. According to an official with the ocean energy bureau, the government could hit the companies with penalties in response.

The panel pinned the ultimate blame on cement at the bottom of the well, which they said failed to block oil and gas from flowing up into drilling pipe and to the rig:

“A central cause of the blowout was a failure of a cement barrier in the production casing string, a high-strength steel pipe set in a well to ensure well integrity and to allow future production. The failure of the cement barrier allowed hydrocarbons to flow up the wellbore, through the riser, and onto the rig, resulting in the blowout.”

Although the inquiry concludes that “the precise reasons for the failure of the production casing cement job are not known,” the panel said BP’s decision to swap cement and drilling mud in a section of casing near the bottom of the well may have contributed. Other potential triggers were contamination of the cement applied at the bottom of the well and the possible pumping of cement past the target location in the well, which would have left the bottom improperly secured.

The federal investigators also highlighted a series of decisions made in the days just before the blast, when BP was preparing to temporarily abandon the well so it could be hooked up to production facilities later. Those decisions “complicated cementing operations, added incremental risk and may have contributed to the ultimate failure of the cement job,” the panel found.

The joint investigation team rapped BP for using only one cement barrier at the site, without additional cement or mechanical barriers in the well, “even though various well conditions created difficulties for the production casing cement job.” And it said that BP failed to perform the production casing cement job in accordance with industry-accepted recommendations.

Finally, the panel found that those decisions and operational risks were never communicated to Transocean.

But Transocean does not escape criticism. The investigators said both BP and Transocean personnel on the Deepwater Horizon missed a chance to combat the cement problems when they misinterpreted unusual readings from a so-called negative pressure test of the cement barrier. The anomalous readings were effectively explained away and attributed to an unconventional theory that proved unfounded, and rig crew ultimately continued abandoning the well.

Workers on the rig floor also failed to respond swiftly to the flow of hydrocarbons up from the Macondo reservoir and into the well until they were gushing with drilling mud into the derrick and onto the rig.

“By then, it was too late,” the panel said. “If members of the rig crew had detected the hydrocarbon influx earlier, they might have been able to take appropriate actions to control the well.”

The three companies centrally involved in work on the Macondo well generally said the report got it right — but for different reasons.

For instance, BP said it agreed “with the report’s core conclusion — consistent with every other official investigation — that the Deepwater Horizon accident was the result of multiple causes, involving multiple parties, including Transocean and Halliburton.”

Transocean said the report “confirms that the primary cause of the incident was the catastrophic failure of the cement in the Macondo well and finally puts to rest all previous allegations that improper maintenance of the (blowout preventer) contributed to the tragedy.”

“As the report rightly concludes, the magnitude of the hydrocarbon release made the ignition and explosion on board the Deepwater Horizon unavoidable,” a Transocean spokesman added.

And Halliburton noted in a statement that the report “accurately places responsibility on BP as the well owner for its operational decisions” and confirms that hydrocarbons were released because of a failure of cement at the bottom of the well, not annular foam cement. Halliburton added:

“If correct, the report attributes such failure to BP’s operational decisions,” including “placing too light of a drilling mud in the rat hole, . . . ignoring industry standards by not properly conditioning or circulating the well prior to the cement job and not drilling a larger hole diameter.”

The report details dozens of recommendations for stiffening the safety of offshore drilling operations, including more safeguards in blowout preventers that are designed as a last defense against surging oil and gas. The investigation team also called for additional mechanical and cement barriers to be used at some offshore wells. And the group said the industry should employ cutting-edge technology for detecting kicks — surges of oil and gas — to help rig crews detect problems quickly and maintain well control.

The Deepwater Horizon disaster killed 11 workers and launched the worst oil spill in U.S. history.

Many of the report’s recommendations also are likely to be wrapped into regulations by the ocean energy bureau, which is on track to unveil a proposal for new drilling safety standards in coming weeks. That rule would build on changes that were imposed rapidly after last year’s oil spill and could take a year or longer to put in place.

Bureau director Michael Bromwich said Tuesday that it was important to proceed deliberately — and that it was unlikely anything in the joint investigation team’s report would require immediate action.

“If the JIT report has conclusions that suggest there is an immediate need to do something — say with respect to blowout preventers — then obviously we would proceed on that basis,” Bromwich told reporters. “Based on what I know right now, I don’t think there is going to be that kind or that set of recommendations.”

The Coast Guard and ocean energy bureau investigation team concluded its public hearings this spring but it has taken months for the group to assemble its final report.

In April, the Coast Guard issued its own findings about the Deepwater Horizon disaster, with a report that focused only on maritime issues under its jurisdiction and not what led to the lethal blowout of the Macondo well.

In part because of its narrow scope, that Coast Guard report honed in on Transocean’s maintenance of the Deepwater Horizon drilling rig and the company’s worker training.

The joint investigation team’s findings are set to be examined on Capitol Hill, beginning with a House Natural Resources Committee hearing on Sept. 23. Panel chairman Doc Hastings, R-Wash., said he is hopeful the report “will give us a clearer picture about what happened, so Congress, industry and the administration can move forward responsibly and appropriately.”

Although proposals to tighten federal oversight of offshore drilling and boost standards for coastal drilling have stalled on Capitol Hill, the federal government has moved separately to bolster requirements for oil and gas companies working on the outer continental shelf.

Read more FuelFix coverage of the report on the Deepwater Horizon disaster:

Joint Investigation Team Report on BP’s Macondo Well disaster