(This article is published in "The Louisiana Weekly" in the March 11, 2013 edition.)
In the second week of a milestone spill trial at U.S. District Court in New Orleans, oil experts last week spoke about the technical and physical challenges inherent in deepwater drilling. In the admiralty trial, Judge Carl Barbier will determine blame between well-operator BP and its contractors Transocean, Halliburton, Cameron and M-I Swaco in the 2010 accident that caused eleven fatalities, many injuries and the nation's worst offshore spill. The companies face stiff penalties, beyond what BP and Transocean have already paid for their roles in the catastrophe.
On Monday, attorneys for Transocean, Halliburton and Cameron continued to cross-examine Mark Bly, BP's group head of safety and operations, from the previous week. Bly was asked about an April 20, 2010 phone conversation between BP's onshore drilling engineer Mark Hafle and Don Vidrine, a BP well site leader on the Deepwater Horizon, less than 50 minutes before the rig exploded.
They discussed an abnormality--a discrepancy between 1,400 pounds of pressure on the drill pipe and zero pounds of pressure on the kill line. That meant that a negative pressure test done the same day and interpreted as okay wasn't successful. The test, a shared responsibility of BP and Transocean, was conducted to see if cementing had sealed leaks in the well.
The conversation between Hafle and Vidrine wasn't included in BP's Sept. 10, 2010 assessment of the accident, known as the Bly report. Bly was asked if he had avoided casting blame on BP's onshore staff in the report. He responded that his intention was "to understand what had happened and what allowed it to happen."
Bly testified that BP's onshore engineers had access to real-time mudlog and other data from the rig on computer screens in their offices.
Bly was asked about his testimony, from the week before, about BP's lack of access to Transocean and Halliburton employees for interviews as having hampered BP's post-accident investigation. Bly said Monday "I think I said we had access to some of the Halliburton folks, but none of the Transocean folks."
An attorney for Halliburton pointed out, however, that the Bly report says "the team used information that was made available by other companies, including Transocean, Halliburton and Cameron." Halliburton's attorney also noted that a court injunction prevented the company from providing BP with certain rig-sample information after the accident.
As for the quality of Halliburton's cement job, an April 20, 2010 email from BP drilling engineer Brian Morel to others at BP, including drilling team leader Greg Walz, drilling engineer Mark Hafle and wells team leader John Guide, was displayed in the courtroom. The message said "just wanted to let know you that the Halliburton cement team they sent out did a great job."
Bly was questioned about why, in preparation for a cement job to close up the well, BP decided to use only six "centralizers," which were needed to ensure that the casing ran down the center of the well bore, when Halliburton recommended using 21 centralizers.
Bly was also asked whether a severe well-control event was under way when efforts were made to activate the blowout preventer or BOP. He answered "in hindsight, it certainly appears to have been."
Between the time the well started to flow on April 20, 2010 and anyone tried to activate the BOP, fifty minutes had elapsed and hydrocarbons were rushing to the surface.
On Monday, geoscience professor Andrew Hurst at the University of Aberdeen, a geologist who worked for Statoil and Unocal, testified that rocks in the Mississippi Submarine Canyon area--where the Macondo well was located--are more fragile than elsewhere in the Gulf of Mexico. Earthquakes occur in the Mississippi Canyon but don't in other parts of the GOM. He discussed two quakes in the canyon in 2006, one of 5.2 magnitude in February, followed by another in April of magnitude 6. The April quake occurred three years before the Macondo well was drilled, and may have destroyed rocks 15,000 to 20,000 feet below sea level, he said.
"In the Mississippi Submarine Canyon, the leak-off pressures are so low, the rocks are so fragile that they're going to require extreme caution when designing drilling programs," Hurst said. Leak-off pressure values are measurements of the maximum drilling mud pressure a well can tolerate before it fractures.
Hurst said Monday that the Macondo well fractured because rocks around the borehole wall disintegrated.
He discussed the Golden Zone, a concept developed in the last decade by a Statoil manager for an area where 90 percent of the world's oil occurs. Declines in temperature as drillers go deeper underground are taken into account in Golden Zone modeling. "The big deal about temperature is that, from looking at all the data from the Gulf of Mexico, we can see there's a clear relationship between temperature and pore pressure," Hurst said. Pore pressure refers to pressure exerted by oil and gas in an underground formation. "And it's pore pressure that we need to be able to predict, so we can understand where and when we're going to locate pockets of high pressure during the drilling of a well or when we go into a reservoir," he said.
But Hurst said it didn't appear that BP used temperature as a predictor of pore pressure in the Macondo well. "They use principles which are actually well known not to be particularly successful and even very, very difficult to make predictions" with, he said.
When asked about use of the Golden Zone concept, he said "my understanding is that many more companies are now actually incorporating thermal controls into their models for predicting pore pressure."
Transocean's senior toolpusher on the Deepwater Horizon, Miles Ezell, with 33 years of oilfield experience, testified Monday and Tuesday. He saved the lives of Transocean employees Wyman Wheeler and Buddy Trahan on April 20, 2010, and the three escaped on a life raft to the offshore vessel Damon Bankston. Ezell testified that Jason Anderson, who he referred to as a top-notch, senior toolpusher, and others on the rig--including BP supervisors--misjudged the results of the negative pressure test done that day.
But, he said, BP's well site leaders on the rig were responsible for deciding how such tests were performed and for interpreting results.
Anderson was one of the workers who died on the rig. Meanwhile on the Damon Bankston, looking across the water at the Deepwater Horizon, "we sat there and watched everybody perish and the rig burn," Ezell said. "You can never take that away. Once this picture is in your brain, it's there."
Ezell said all deepwater wells are "very difficult and have their own unique challenges." He's still employed by Transocean but is now working in a training center in Brazil.
On Tuesday and Wednesday, Ronny Sepulvado, a BP well site leader, testified. When asked why the Macondo well was behind schedule, he said "they had another rig on the well and a storm came through and messed up some of the electrical equipment on it." That rig was removed. "Then they moved the Horizon on the well, and we had several lost circulation events during drilling. I think we took a kick during drilling. So we were behind." A kick is an entry of gas or fluid into the well, capable of causing a blowout.
When asked if BP adopted an "every dollar counts" culture on the Deepwater Horizon, Sepulvado said "yes, we did." He explained it was implemented "by getting equipment out later for jobs and getting it in earlier, and not letting it sit on the rig for long periods of time." He said safety had not been comprised for every-dollar-counts, however. Sepulvado wasn't on the rig when it exploded because his well control certificate was about to expire.
Also testifying Wednesday was Canadian drilling consultant Richard Heenan, a witness for the federal government. He spoke about the negative pressure test on April 20, 2010, and said "I couldn't believe that, given what they saw, people on the rig came to the conclusion it was a successful test."
Heenan continued "they had run the test and declared it successful, and they were moving ahead with the next phase of the operation." Had the test been viewed as unsatisfactory, it would have been rerun, he said.
On Wednesday and Thursday, federal expert witness Glen Benge, an oil-field cement consultant with 36 years of experience, said testing done by Halliburton on its cement mixture up to April 17, 2010 showed "anomalous" or problematic results. Those results should have been examined to see if the slurry needed to be redesigned. BP was the final decision maker on using the cement job, he said. Though BP knew of problems with the cement mixture, it was not redesigned.
Moreover, BP's decision to use six centralizers, rather than 21 advised by Halliburton, left a narrow space around a side of the drill pipe, Benge said. Cement pumped around the pipe couldn't fill the slim side, leaving a channel which filled with drilling mud and allowing hydrocarbons to travel to the surface.
Cement pumped into the Macondo well on April 19, 2010 had not hardened when a negative pressure test was run the next day, Benge also said.
Federal expert witness Rory Davis, a Ph.D. mechanical engineer, testified Friday that lack of maintenance to the blowout preventer, including batteries not being replaced, contributed to the BOP's failure. A BOP is a large, mechanical device, used to control and seal wells. BP was aware of these maintenance issues, he said.
On Monday, the trial continues with cross-examination of Davis about the BOP. The trial, which is open to the public, should extend into May unless a settlement is hammered out before then. The trial runs from 8:00 a.m. to 6:00 p.m. Monday to Thursday in Eastern District Court on Poydras St. in New Orleans. If you plan to visit the court, bring a photo ID, be prepared to clear a security checkpoint and dress warmly because the courtroom is frigid. end