Experts clash on estimates of oil spilled into Gulf

A sparring match between some of the world’s top scientists over how much oil spewed into the sea following the 2010 Gulf of Mexico disaster is heating up as a civil trial is set to resume next month.

The high-stakes battle of the experts is taking shape in BP’s quest to cut the Clean Water Act fines it will have to pay for the worst U.S. offshore oil spill ever.

Recent court filings that include copies of the expert reports show U.S. District Judge Carl Barbier will have his work cut out for him in deciding the spill total following a month of testimony beginning Sept. 30 from witnesses for BP, Anadarko and the Justice Department.

BP scored a victory last week when a federal magistrate judge ruled that it can use a report from one if its key experts, Andreas Momber, whose research involves erosion of minerals-based materials such as cement.

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Momber has concluded that the cement in BP’s Macondo well eroded slowly, possibly impeding some of the flow “for a substantial portion of the spill.” Government experts counter that the cement eroded within two days, allowing oil to flow unimpeded from nearly the beginning of the disaster.

Momber, a lecturer in the Department of Geo-Resources and Materials Technology at the Aachen University of Technology in Germany, doesn’t say in the report he issued in May how much oil he believes spilled during the nearly three months the runaway well was flowing. But his analysis serves to undercut the validity of the government’s assertion that 4.9 million barrels of oil was discharged from the well.

“It is scientifically unsound to assume that the cement would have completely eroded within hours or a few days,” Momber wrote in his report.

Momber said the government’s experts assume erosion rates that are 10,000 to 100,000 times greater than any reported in the extensive literature devoted to concrete erosion.

“Even if the erosion rate is doubled due to the possibility that the well cement had a high porosity, the complete erosion of the well cement would not occur in two days or anything close to that,” he said.

Anadarko sees little risk

BP, based in London, was the majority owner of the well that blew out a mile beneath the sea off Louisiana. Anadarko Petroleum Corp., based in The Woodlands, owned a minority stake in the well.

While Anadarko is participating in the second phase of the trial, its financial exposure is unclear. It has said it doesn’t expect a significant financial risk from civil fines because it had no involvement in the drilling of the Macondo well.

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It also agreed in 2011 to pay $4 billion to BP in exchange for protection from most spill-related damage claims – but that agreement did not cover fines, penalties and punitive damages that could result from the civil trial that resumes next month.

MOEX, a subsidiary of Japan’s Mitsui Corp., which had a 10 percent stake in Macondo, agreed to pay $1 billion to BP to settle claims.

Only owners could be fined

Halliburton, which provided the cement for the blown-out well, and Transocean, which owned the rig that exploded and sank following the well blowout, have been barred from calling witnesses during the second phase of the trial because only the well’s owners face possible fines over how much oil spilled.

The rig explosion killed 11 workers.

The first phase of the trial, which ended in April, addressed the causes of the accident and who was responsible. Barbier has not yet made any substantive rulings as to BP, Transocean and Halliburton. The judge did toss gross negligence claims against blowout preventer maker Cameron and well fluid provider M-I Swaco, a unit of oil field services company Schlumberger.

Several expert reports filed in recent months specifically address the issue of how much oil spilled.

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In one of the reports, BP expert Martin Blunt, a professor in Imperial College’s Department of Earth Science and Engineering, said he calculated that 3.26 million barrels of oil were released from the Macondo well. Another BP expert’s estimate is lower than that.

Reports from government experts filed in court back up the government’s official spill total, which it released in August 2010 after scientists from all over the country analyzed well data and other factors.

The government has agreed not to include the 800,000 barrels of oil collected at the wellhead through various siphoning methods in calculating the penalties it seeks against BP.

By that reckoning, the government estimates that 4.1 million barrels of oil entered the Gulf, and Blunt’s estimate is 2.46 million barrels.

Up to $17.6 billion

Based on the government’s estimate, BP would face up to $17.6 billion in Clean Water Act penalties, if Barbier finds that the company was grossly negligent. He has not yet ruled on that key issue. Based on Blunt’s calculation, the maximum penalty with a finding of gross negligence would be $10.6 billion.

Barbier has said in court that it will be difficult for him to decide on a spill total. The war of the experts adds to the challenge.