Wednesday, April 16, 2014
By Michael Kunzelman
The Associated Press
(Continued from page 1)
“Basic principles of oil production hold that reservoir pressure depletes and flow rates wane over time,” Justice Department attorneys wrote.
BP’s experts concluded that flow rates increased over time, due in part to the erosion of steel rams on the rig’s blowout preventer. Martin Blunt, a BP expert who is a professor of petroleum engineering at Imperial College in London, also took other factors into consideration, including the “compressibility” of the rocks in the reservoir BP was drilling.
“In assessing the data, Dr. Blunt uses a conservative lens,” BP attorneys wrote. “Dr. Blunt accounts for fundamental geological facts and principles of physics acknowledged by United States experts but omitted in their flow calculations.”
Calculating the rate that oil was flowing from the well has been a contentious issue from the beginning of the disaster.
Marcia McNutt, who was director of the U.S. Geological Survey at the time of the blowout, led the government’s Flow Rate Technical Group and frequently interacted with BP officials while its engineers scrambled to seal the well. In videotaped testimony shown to Barbier last week, McNutt said it didn’t appear that anyone from the government was inside BP’s “circle of trust” when it came to sharing data about a procedure called “top kill” that failed to seal the well.
McNutt also said it took longer for her team of scientists to arrive at a flow-rate estimate because they got poor data from BP.
“Did you feel that BP was not a willing partner when it came to flow rate?” a lawyer for Deepwater Horizon rig owner Transocean Ltd. asked McNutt.
“There was this tenseness,” McNutt said. “It was almost kind of a chill in the room when flow-rate issues came up.”
Timothy Crone, a professor of marine geophysics at Columbia University, was the lead researcher on what was billed in September 2010 as the first independent, peer-reviewed study of the leak’s volume. Crone and a colleague analyzed underwater video to arrive at an estimate that closely mirrors the federal government’s current calculation of how much oil escaped the well.
Crone said he is surprised the topic is still being debating three years later.
“The majority of scientists who worked on the problem are in agreement,” he said. “I can understand why BP wants to make it a question again, but in my opinion it’s not.”