Gulf oil spill: Pressure test was subject of debate before explosion, witness says

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Before the April 20 explosion of the Deepwater Horizon, employees aboard the oil rig voiced “confusion” about the interpretation of a key safety test that could have led them to take different action and possibly avoid the disaster that killed 11 crew members and started the worst offshore oil spill in history, according to testimony Tuesday at a federal hearing in Houston.

Daun Winslow, a Transocean performance manager who was visiting the rig the day it exploded, testified that while he was touring the driller’s shack, a key control room aboard the rig, he saw BP well-site leaders and other key decision makers discussing a pressure test.

‘It appeared that there was some confusion about some pressures or volumes circulated, or something along that line. And I heard the word negative test,” Winslow said.

Winslow said he suggested the tour group move along, saying, “it wasn’t a good environment to have a tour group there.”

The testimony demonstrated the confusion over a ‘negative pressure test,’ which is done to see if there are any dangerous bubbles of natural gas that might flow out of the well into the riser pipe leading to the rig.

An expert witness testified in July that the crew of the Deepwater Horizon did not conduct the negative pressure tests properly. If the test was done correctly and revealed that dangerous gas bubbles were lurking in the well, the crew might have taken different action to avoid disaster.

Instead, BP continued with a procedure that left open avenues that could allow bubbles to flow up the well into the belly of the rig, where it exploded.

Winslow later changed his testimony, saying, “I didn’t hear any confusion.”

The testimony was heard in Houston at a joint hearing Tuesday of the U.S. Coast Guard and Department of Interior, which is investigating the cause of the worst oil spill disaster in history.

-- Rong-Gong Lin II in Houston