Probe leaves questions about blowout preventer

WASHINGTON — The hydraulic system that powered the blowout preventer at BP’s failed Macondo well may never have had the capacity to stop last year’s Gulf of Mexico spill or any other such emergency, investigators say.

But that possible deficiency – and other findings about the equipment used as a safeguard on thousands of wells – may never get a full airing.

A government-run examination of the device ended in March, and a second round of testing was open only to the Justice Department, the oil spill victims and the three companies connected to the Deepwater Horizon disaster.

“It’s only fair to the industry that they know what happened,” said Gordon Aaker, president of Kingwood-based Engineering Services.

He said too many questions about the Macondo blowout preventer remain for the companies that use similar devices to be confident of avoiding a repeat of the disaster on April 20, 2010.

Engineering Services took par­t a four-month government-led examination of the blowout preventer, or BOP, on behalf of the Chemical Safety Board, an independent agency that also is probing the disaster.

That probe was meant to aid a federal investigation into the root cause of the explosion that killed 11 workers and the resulting oil spill that dumped 4.9 million barrels of crude into the Gulf last year.

To lead the testing, the government hired forensic analysis firm Det Norske Veritas, which concluded in March that cutting rams on the blowout preventer were unable to slash through and seal pipe that had buckled and been pushed askew by flowing oil and gas.

BP sought additional tests, and a federal judge okayed the plan. But the court barred anyone who wasn’t a party in broad oil spill litigation — including the Chemical Safety Board and its investigators — from the second phase of testing that ended late last month at a NASA facility in New Orleans.

Lawyers at the Justice Department concluded that they would not assert CSB’s jurisdiction in court, amid uncertainty about whether the agency was authorized to probe the incident.

Company representatives and other stakeholders are set to do a final walk-through of the testing site today.

It is unclear whether findings from the second phase of testing will be included in a report expected late this month from a federal investigation team or will be made public in any other forum.

Parties to the probe won’t say explicitly whether they will release the information or seek to prevent its release.

A spokeswoman for the federal agency that oversees offshore drilling would not say whether regulators would obtain the data, which could be used in updating government standards for blowout preventers.

“The process of making offshore energy development both safe and sufficient to help meet the nation’s and world’s energy demands will never be complete. It is a continuing, ongoing dynamic enterprise,” said Melissa Schwartz, a spokeswoman for the Bureau of Ocean Energy Management, Regulation and Enforcement. “We will continue to monitor relevant reviews, studies and investigations for information that could inform future rule-making or increase safety enhancements.”

With testing complete, companies are fighting over the fate of the blowout preventer. Transocean, which owned the Deepwater Horizon rig, told a federal judge that it should take possession of the hulking 300-ton device. But BP wants the government to hold on to the equipment.

Det Norske Veritas’ report from the initial four-month examination of the device left unanswered questions, including precisely why a key component called the upper annular failed to seal around drill pipe at the Macondo wellhead on the ocean floor.

Had that annular sealed, it might have kept gas from traveling up a mile of pipe to the Deepwater Horizon, where it ignited.

“One of the most important parts of the phase two testing was to assess the condition of the upper annular and why it failed to close,” Aaker said. “Because that, ultimately, is why (11 men) died. If that thing had closed, it would have saved lives.”

Investigators at Engineering Services also want to know more about the hydraulic system that powered the blowout preventer’s automatic shut-in systems. They have questioned whether the system ever had enough pressure stored in containers called accumulator bottles to drive shear rams through the 6 5/8-inch-diameter drill pipe that was used at the site.

While the stored pressure met existing industry standards and federal regulations, it was substantially lower than indicated on drawings for the rig. Engineering Services investigators said a higher pre-charge pressure would have been relatively easy to set and would have provided an energy reserve for the unexpected.

Without enough pressure, any automatic shut-in activation of the BOP risked a partial, incomplete shearing of the pipe and a gusher like the one in April 2010 – whether the BOP was activated by a surge of oil in the well or another trigger.

For instance, a blowout preventer can be triggered automatically if the BOP loses its hydraulic and power connections with the rig.

Engineering Services’ analysis of a formula provided in 2008 by Cameron International, the Houston-based company that made the BOP, concluded that an operating pressure of 4,200 pounds per square inch is needed at the moment cutting rams push through the pipe.

But a regulator on the Deepwater Horizon’s BOP limited the delivery pressure to the blind shear rams to 4,000 psi.

Additionally, based on Engineering Services’ calculations, the shearing rams probably would have received just 3,700 psi of hydraulic pressure at the moment they confronted the pipe, 500 psi short of what Cameron recommended in 2008 as a “high reliability” value.

Cameron’s 2008 formula updated previous guidance the company had issued in 2001. At that time, Cameron documentation simply said blowout preventers outfitted like the one on the Deepwater Horizon were capable of cutting 6 5/8-inch thick drill pipe weighing 27.6 pounds per foot.

Bill Ambrose, managing director for Transocean’s North American division, insisted that the hydraulic pressure stored in the accumulator system was sufficient to power the shearing rams.

“It did have enough energy to operate the system as designed,” Ambrose said.

A spokesman for Cameron declined to comment.