This article is published in "The Louisiana Weekly" in the Oct. 14, 2013 edition.
At the Macondo spill trial, number crunching or quantification of the oil flow started Monday in U.S. District Court in New Orleans, with Judge Carl Barbier presiding. The United States is on one side with a figure of about 5 million barrels for the disaster that commenced in late April 2010, versus BP and Anadarko on the other with 3.26 million barrels. By Wednesday afternoon, the feds had rested their case on quantification, and BP began calling its witnesses Thursday.
In Monday's opening statement, government attorney Steve O'Rourke said the United States would present four experts using different methodologies. In modeling by these witnesses, principle engineer Ronald Dykhuizen of Sandia National Laboratories considered the well's capping stack data; retired Sandia senior scientist and engineer Stewart Griffiths examined blowout preventer data; University of Tulsa engineering professor Mohan Kelkar used a material balance approach; and Mehran Pooladi-Darvish, senior director at IHS Inc., relied on reservoir simulation. The upshot of these studies was "they all match up at around 5 million barrels of oil total," O'Rourke said.
Those four experts used data provided by BP during the spill, and "they each conclude that the rate at the beginning was about 62,000 barrels of oil per day," O'Rourke said. "By the last day, July 15, 2010, it was about 53,000 barrels. Adding those days up, it was 5 million barrels."
About 812,000 barrels were collected during the spill by the Top Hat containment device, the capping stack and drilling vessel Helix Q4000, O'Rourke said. That left 4.2 million barrels released out of the five million barrels that exited the well, he said.
The fed's science team for the spill included three national laboratories associated with the U.S. Dept. of Energy--Sandia, Lawrence Livermore and Los Alamos, together known as Tri-Labs. The team, led by Sandia director Tom Hunter, offered assistance in the spill response, O'Rourke said.
"The defendants might present a case to you that these Tri-Labs people were just political hacks, put there by the Administration to generate a high flow rate," O'Rourke said. "But Dr. Hunter will come and testify to you that there was no conspiracy, no Administration agenda. They were there to try to get the right answers and to help." When BP needed to shut in the Macondo well, it relied on National Labs' calculations, he said.
O'Rourke said the defendants won't present a final, daily flow rate during the quantification trial. "They will nitpick at our experts for sure, but they will not tell you what the actual flow rate was," he said.
The feds are using the oil industry's definition of barrels in their legal battle against BP. "In the Clean Water Act, the penalty only applies to barrels, defined as 42 gallons at 60 degrees Fahrenheit," O'Rourke said. "It doesn't state what pressure. But in the industry, there is a term called stock-tank barrel. And this is 42 gallons at 60 degrees Fahrenheit at one atmosphere pressure or sea level pressure."
Barrel measurement starts in the reservoir, O'Rourke said. "What happens is as these barrels come up and the pressure abates, the gas comes out--comes out as a solution, with off gases," he said. "So by the time it gets to the surface of the water, a barrel down in the reservoir might be only half a barrel of liquid left."
O'Rourke said in addition to its litigation experts, the government panel known as the Flow Rate Technical Group, assembled by Coast Guard Admiral Thad Allen, reached a consensus on a 53,000- barrel flow on the final day of the spill. After that, the presidential Oil Spill Commission in October 2010 said a consensus had emerged between federal and independent scientists, using different methods, that roughly 5 million barrels were released.
In comparison to 5 million barrels, the 1989 Exxon Valdez spill in Alaska totaled 262,000 barrels. "So what we have here is a Valdez worth of oil spilling out every four and a half days," O'Rourke said.
BP lied to Congress about the flow, O'Rourke said. "They later told their shareholders in their Securities and Exchange Commission filings that the flow was 4 million barrels, that 3.2 was collected," he said. "With those statements, they are going to come here and tell you that it wasn't 4 million, it was 3.26 million" or lower. He said BP arrived at its current numbers by cherry-picking data and ignoring information from the spill response.
"At the close of the evidence, your Honor, we will ask you to find as a fact that the beginning of the flow period, about 62,000 barrels of oil per day were coming out; that by the end about 53,000 barrels were coming out," O'Rourke said. "If you add those days together, it was 5 million barrels."
In his opening, attorney Mike Brock for BP and Anadarko, said during the previous week's source-control trial in New Orleans, witnesses testified about daily changes in the Macondo well during the spill. "The United States is going to present evidence that relates to a day-by-day calculation over 86 days, when we are in a position where the wellbore is changing daily," he said.
During the 85 days, many "geometry changes" occurred because of the structure of and activities affecting the well, including its riser, metal erosion and junk shots, Brock said. Junk shots were injections of golf balls and other objects to obstruct the flow.
"The government first came out with their flow rate estimate of around 5 million barrels on August 2, 2010 after a few hours of work," based on a model that assumed the well geometry had not changed in 85 days, Brock said.
Brock said some areas of the oil reservoir weren't connected, and not all of the oil below could flow in the well. But he said the feds assumed one hundred percent flow into the well. "So that's one big difference that we have with the government," he said.
He said in late July 2010, the feds were under pressure to come up with a daily and total flow to announce to the public as wild rumors flew about unaccounted-for oil. "This five million figure that they're using in this case now is one that was designed to be a quick and dirty number for negotiation purposes, but not good science," he said.
BP has a much lower spill number than the feds. "It's BP's position that using the industry standard material-balance equation, that the amount of oil that left the well was 3.26 million stock-tank barrels," Brock said. The material balance method considers oil in place before the spill, and based on the principle of conservation of mass, calculates the amount that's left in the well afterwards, he said. That's a typical way for industry to figure out what occurred, he said.
In testimony Tuesday, Stewart Griffiths, a retired Sandia fluid dynamics and applied math expert, admitted he had no oil industry experience but defended his Macondo model--which is based on periodically measured pressures and flow rates of collected oil, along with fluid dynamics principles--to calculate what spewed over 86 days.
Under questioning from government attorney Tom Benson, Griffiths said that before May 8, 2010, erosion of metal parts after the Deepwater Horizon rig exploded in late April affected cumulative discharge. "Erosion is a phenomenon that can occur very, very rapidly, and then slows once apertures get opened a little bit," he said. After May 8, 2010, the blowout preventer's erosion had little impact on the well's cumulative discharge, he said. Griffiths concluded that erosion in the reservoir and wellbore reduced total discharge only slightly. BP contends that erosion lowered discharge to a greater extent.
"At the end of the day, I have the highest confidence in 5.0," million barrels having escaped the well, Griffiths said. "I've actually checked these calculations more carefully than I have ever checked any calculations in my career."
On Wednesday, government witness Aaron Zick, a thermodynamic modeling expert, testified about fluid phase behavior. He was followed by professor Mohan Kelkar, who was questioned about his material balance modeling, uncertainty over oil in the reservoir before the spill, and his flow calculation of 54,000 barrels on the last day of the spill.
In testimony Wednesday, Mehran Pooladi-Darvish, a reservoir engineering expert, said his wellbore and reservoir model put total oil released at 5 million to 5.3 million stock-tank barrels.
BP started calling its witnesses Thursday. Martin Blunt, Imperial College London petroleum engineering professor, was asked about Macondo reservoir characteristics. He said the share of oil that could flow into the well from the reservoir was between 87 and 90 percent, which is a very good connectivity rate. Nonetheless, in his analysis 3.26 million stock-tank barrels exited the Macondo well in the spill.
After a day off Friday and Columbus Day Monday, the trial will resume on Oct. 15. Penalties against BP for barrels spilled will be the subject of a later trial and could be assessed in early 2014. end