WASHINGTON — An inadequate underwater cement job during the deepwater drilling process is emerging as a potential cause for the devastating oil spill off the Louisiana coast in the Gulf of Mexico.
Officials haven't said what they think caused the April 20 explosion that led to the sinking two days later of the Deepwater Horizon drilling rig, owned by Transocean Ltd. But industry speculation points to a process where cement is used to seal cracks in the ocean floor surrounding the tubing through which crude oil flows.
Transocean operated the drilling rig under contract for British oil giant BP Plc., the largest oil producer in the U.S. portion of the gulf and a company with a spotty safety history. Transocean has said the global construction titan Halliburton had just completed "cementing" the 18,000-foot-long well around the time of the explosion.
In a statement Friday, Halliburton confirmed that it was the "cementer" hired for the job and said it had completed its job about 20 hours prior to the explosion.
"The cement slurry design was consistent with that utilized in other similar applications," the company said. It said all procedures had been "in accordance with accepted industry practice approved by our customers."
"It is premature and irresponsible to speculate on any specific causal issues," the statement said.
"We cannot get ahead of ourselves with respect to the facts of this incident," Guy Cantwell, a spokesman for Transocean in Houston, told McClatchy.
Before conducting a complex ultra deepwater drilling operation like the one that Transocean was undertaking for BP, all the contractors meet weeks in advance to plan the smallest details. What isn't known yet is why a fairly routine operation turned deadly, with 11 rig workers killed in the initial blast that eventually sunk the Deepwater Horizon.
"I think this is not an equipment problem, I think this is a human problem. I don't know the details, but from where I'm standing they had a blowout, and a blowout is something that is a human problem," said Rene Ritter, a Canadian consultant on ultra deepwater drilling projects across the globe. A blowout is oil-drilling jargon for a sudden, uncontrolled surge of natural gas or oil from a well.
Cautioning that he has not worked with BP in the Gulf of Mexico, Ritter said it's extremely rare to have catastrophic equipment failures.
"It is somebody not paying attention to what's going on, bad planning, but a blowout is something that doesn't just happen like that _ 99 percent of that is human behavior," said Ritter, who helped Brazil pioneer its deepwater drilling program.
Another potential cause for a blowout would be the failure of a hydraulic safety valve system designed to control pressure increases. The valve was made by Cameron International Corp.
If "cementing" is the cause, it could spell new troubles for Halliburton, whose work was also suspected in a well explosion that took place last August in the Timor Sea near Australia. It took 71 days to fully cap and contain that spill, according to Australia's Sunday Times. The official investigation is still ongoing, but cementing was the main area of investigation, the head of the inquiry has said.
BP's safety record in the United States is spotty. Last October, it was hit with a record $87 million workplace-safety fine for failing to take corrective steps and new violations after a 2005 explosion at its Texas City refinery that killed 15 workers MORE FROM MCCLATCHY