HOUSTON — An official for Halliburton, the company hired by BP to perform a critical step in the process for closing the well connected to the Deepwater Horizon oil rig, testified Tuesday that days before the rig exploded he had raised concerns to BP about its plan for executing the procedure, but that he continued with the job anyway.
The official, Jesse M. Gagliano, a shore-based technical adviser, told federal investigators here that he had recommended that BP use a greater number of devices called “centralizers” in the well for the tricky step known as cementing, which is a method of strengthening the well to control pressure from the oil and gas. He said he was ignored.
Centralizers help cement flow evenly around an oil well before hardening, and using 6 of them — instead of the 21 that he recommended — made the well more likely to need additional cementing, Mr. Gagliano said.
Investigators say they believe that the cement poured by Halliburton may have failed under tremendous pressure on April 20, producing the oil rig explosion that led to the largest deep-water oil spill in United States history.
Mr. Gagliano and a lawyer for BP disputed whether Halliburton or BP should be responsible for the final cement plan.
“This reflects your best engineering judgment and analysis, doesn’t it?” asked Rick Godfrey, a BP lawyer, referring to a report prepared by Mr. Gagliano two days before the disaster that permitted the six centralizers.
“No, my best engineering analysis would have been to run 21 centralizers,” Mr. Gagliano said.
The testimony, before an eight-member panel of federal government investigators, provided a fuller portrait of workers’ potentially risky decisions in the days before the disaster: not conducting a test called a “cement bond log,” not using a potentially safer type of well liner, and not conducting a “bottoms-up” test of the drilling solution in the well.
In a report to BP two days before the disaster, Mr. Gagliano noted that a reduced number of centralizers could cause a “severe gas flow” problem. By the morning of the disaster, BP had more centralizers flown to the rig, but decided not to install them, Mr. Gagliano said.
But internal Halliburton documents suggest that company employees believed that the cement job had been conducted properly by the day of the disaster.
“We have completed the job and it went well,” one Halliburton worker, Nathaniel Chaisson, wrote in an e-mail to colleagues on the morning of the disaster. “Full returns were observed throughout.”
Another internal Halliburton report from that day said, “Cement job pumped as planned.”
Reports by Halliburton experts on the company’s Web site suggest that the company is prepared to control such “severe gas flow” problems as Mr. Gagliano forecast. In 2008, a cementing expert, Ron Crook, recommended that such problems be contained by changing the ingredients and consistency of the cement and its placement in the well.
“In wells with severe levels of gas migration,” the article states, the risk of a gas flow problem “can be reduced to a safe level” by adjusting those other factors.
A reduced number of centralizers have been used on other wells in the Gulf of Mexico, Mr. Gagliano said. But he said the plan for the Deepwater Horizon made him uncomfortable.
“Hey, I think we have a problem here,” Mr. Gagliano said he told shore-based BP officials when he learned that six centralizers were being proposed.
But BP overrode his objections, he said. “BP had made their decision,” he said.
Earlier in the hearings, an employee for Transocean, the rig’s owner, testified that his company provided financial bonuses to workers based in part on how quickly they made equipment repairs. The testimony from Daun Winslow, a performance division manager on the rig at the time of the disaster, furthered concerns that financial pressure might have trumped safety on the rig.
The amount of “downtime” for a rig was a small factor in calculating bonuses, Mr. Winslow testified, although other factors, including the rig’s environmental impact, customer satisfaction, individual performance and safety were also considered.
“Safety was a bigger component than downtime,” Mr. Winslow said. “Safety is one of our core values.”
Under questioning from BP’s lawyers, Mr. Winslow said Transocean lost as much as $500,000 a day in rig rental fees paid by BP when mechanical repairs prevented drilling for oil.
Mr. Winslow also faced questions about an emergency on another Transocean rig in the North Sea that bore similarities to the Deepwater Horizon disaster. He testified that he had never heard of the near-disaster in the North Sea in December, even though Transocean internal documents suggest that the company intended to make critical changes to its oil well safety procedures.
Like the disaster in the gulf, the North Sea emergency involved dangerous pressure levels in the well, a failure to detect those pressures in time, a risky plan for sealing the well and an emergency order for the crew to evacuate to lifeboats. Mr. Winslow said Tuesday that knowledge of the episode would have been helpful, although he noted differences to the disaster in the gulf.
“I believe this would increase the awareness of anyone in the drilling industry,” he said.