Pressure problems noted about 20 minutes before Deepwater Horizon explosion
May 27, 2010, 7:57PM
Drillers on the Deepwater Horizon began having trouble with pressure from the Macondo well about 20 minutes before the fatal explosions that killed 11 workers, destroyed the rig and caused
the largest oil spill in U.S. history. But
no one tried to shut off the well until after the fire erupted, according to testimony from several survivors at hearings Thursday in Kenner.
New testimony from Chief Mate David Young raised questions about why the well wasn't shut down before a kick of gas shot up the rig's riser, spewing mud and seawater and taking the vessel's senior officers by surprise. The top two Transocean officers on the rig at the time testified Thursday that anyone who had a concern about safety could have called a "timeout" to shut off a well that might go out of control, but that was never done
A joint investigative panel of the Coast Guard and Minerals Management Service held its fourth day of
hearings to determine what went wrong on April 20. The hearings have been long and complex because of the technical nature of the drilling industry and because several companies' employees played a role in the disaster; BP owned the well, but leased the rig from Switzerland-based Transocean, which provided most of the rig workers. Halliburton was hired to place cement seals in the well, M-I SWACO provided drilling mud, Schlumberger had a team on the rig to run tests and other companies provided key pieces of equipment.
Young, whose job included providing cement slurry to Halliburton contractors, said he stopped by the rig's drill floor about 9:30 p.m. on April 20 to see when they would need the cement. He said he found drilling supervisor Jason Anderson and chief driller Dewey Revette there, trying to analyze some problematic pressure readings from down in the well.
Anderson and Revette were among the workers killed in the accident
"They had a concern with differential pressure," Young said. "They said it would be a little longer to figure it out, for the cement job meeting. They were seeing a differential pressure. I didn't ask any questions about it."
Young said that after he went to another office to report that the cement job would be delayed, he heard a release of gas. "I knew something was up so I went to the bridge," he said.
Also on the bridge was the rig's master,
Curt Kuchta, who was giving a tour to BP executives who had flown in to celebrate the rig's safety record. Kuchta testified the VIPs were "basically playing a video game," using a simulator of rig controls on the bridge that was usually used for crew training.
The other top officer on the rig, offshore installation manager Jimmy Harrell, was in the shower when the first of several explosions happened about 9:49 p.m., he testified.
It wasn't until Harrell stumbled out of the shower, put on some clothes, arrived on the bridge and consulted with Kuchta that the captain said he ordered the activation of shear rams on the blowout preventer and the emergency disconnect system at 9:56 p.m., according to their testimony.
Harrell said he believed the explosions somehow disabled the blowout preventer's control panel and the emergency disconnect system, neither of which worked.
Young wrote in a statement to Coast Guard investigators immediately after being rescued that the drillers were "having well issues," but he testified Thursday that he didn't realize that meant they "had lost control of the well."
Capt. Hung Nguyen, chairman of the joint Coast Guard and Minerals Management Service investigative panel, has raised concerns in the hearings about a lack of clarity over who was ultimately in charge on the oil rig. Noting that Transocean puts the offshore installation manager in charge when the unit is drilling, and that the captain is in charge when the vessel is "under way," Nguyen said that neither top official seemed to have "visibility" of the events that led to the disaster.
Harrell testified that
BP was constantly changing the well plan over the final days, including the significant addition of a 9 7/8-inch metal casing that tapered to 7 inches at the bottom and lined the inside of the well.
A draft of BP's internal investigation, which was released Tuesday by the House Energy and Commerce Committee, says that particular casing suffered a "loss of integrity" and "created a path" for gas to shoot up to the rig.
Harrell said cement used to close in the casing was infused with nitrogen, and it was the first time he'd ever seen this relatively new type of faster-curing cement used at such depths. He said he'd heard of problems with nitrogen getting into the well and acknowledged he may have reacted to the planned use of that type of cement by saying, "Well, I guess that's what we have those pinchers for," referring to the last-ditch shear rams that would be needed to shut the well in an emergency.
But when pressed, he denied being worried about the cement plan
Harrell also said he was handed a plan on the morning of the disaster that called for his crew to displace drilling mud with lighter seawater without conducting a critical negative pressure test on the well. Harrell said he would never do such a thing and discussed it with BP's company man, Robert Kaluza.