A Halliburton engineer has testified he warned BP its design for the Macondo well was flawed. The deepwater exploration well, which had struck oil in the Gulf of Mexico, would be susceptible to surges of natural gas without changes to the design, testified Jesse Gagliano, a shore-based technical adviser assigned by Halliburton to work with BP.
Mr Gagliano appeared this week before a US government panel. The oil company had hired Halliburton, the international oil and gas services firm headquartered in Houston and Dubai, to install a steel liner, or casing, inside the well. On April 20, gas surged up the well bore, triggering an explosion that killed 11 rig workers and caused the biggest oil spill in US history. Five days before that, Mr Gagliano had urged BP to use 21 devices called "centralisers" to ensure the steel casing could be properly secured to the rock, according to his testimony. Instead, BP opted to stick with a design using six centralisers.
"My best engineering analysis would have been to run the 21 centralisers," Mr Gagliano told the eight-member joint US coastguard-interior department panel, which is investigating the accident that sank the Deepwater Horizon drilling platform. The Halliburton engineer said he told BP officials in Houston on April 15 there was a "high probability" of gas flowing through the cement unless they made changes. He said he and two BP engineers spent the rest of the day studying the problem.
"By the end of the evening, we had determined that 21 centralisers would take care of the issue," Mr Gagliano testified. The BP engineers went as far as arranging to fly more centralisers out to the rig but later reversed that decision, reportedly out of fear that using more of the devices could cause the sleeve-like casing to get stuck as it was inserted into the well. Centralisers are used to keep the casing accurately positioned in the middle of the well bore as cement is pumped into the space between the liner and the rock. The cement is intended to create a seal to control pressure from oil and gas in the reservoir.
"Who cares, it's done, end of story, we'll probably be fine and we'll get a good cement job," Brett Cocales, one of the BP engineers, wrote in an April 16 e-mail that came to light two months ago. He added that BP could fix the cement later if necessary. Other e-mails indicated that John Guide, the leader of the BP engineering team assigned to the well, objected to using extra centralisers because they were not consistent with the existing well design and might cause unforeseen problems.
Mr Gagliano said BP did not inform him of its decision. Instead, he learnt of it on April 18 from Halliburton workers aboard the rig. He also learnt that BP had not followed other Halliburton recommendations, such as flushing out the well with fresh drilling fluid before pumping in cement. Asked by investigators why he did not at that point object more strongly to BP's decision, Mr Gagliano said that if the cement job failed, BP could still have pumped in more cement to fix the problem.
But BP did not test the integrity of the cement job. Mr Gagliano said he had not recommended such a test. Richard Godfrey, a lawyer representing BP, pointed to e-mails from Mr Gagliano and other Halliburton employees that said the operation had been successful. "We have completed the job and it went well," Nathaniel Chaisson, a Halliburton worker, wrote to colleagues on the morning of the disaster.
"Halliburton was fully aware of the Macondo well's key design features, including the use of six centralisers around a long string production casing," BP said yesterday in a statement. "If Halliburton had significant concerns about its ability to provide a safe and high-quality cement job in the Macondo well, then it had the responsibility and obligation to refuse to perform the job. "As the evidence today makes clear, Halliburton had no such concerns, which is why its engineers proceeded with the job."
Brian Morel, a BP engineer who helped oversee the cementing operation, was also scheduled to testify on Tuesday but declined to appear. He cited his right under US law not to incriminate himself. Mr Cocales, the engineer who wrote one of the e-mails, is scheduled to testify tomorrow. @Email:firstname.lastname@example.org