Gulf oil spill: Why raise the faulty blowout preventer? It's evidence.
Drilling on the relief well has stopped while BP prepares to raise the failed blowout preventer from the sea floor. The effort is not just a safety precaution. The equipment is also evidence that may reveal how the Gulf oil spill happened.
The 450-ton blowout preventer resting a mile below the surface of the Gulf of Mexico is set to become Exhibit A in a Justice Department investigation into what caused the explosion aboard the Deepwater Horizon rig, killing 11 men, sinking the platform, and resulting in the biggest oil spill in US history.Skip to next paragraph
Subscribe Today to the Monitor
Preparations are under way for the massive blowout preventer stack of valves – a unit taller than a school bus is long – to be brought to the surface. The piece of equipment, says Robert Bea, a former engineer for Shell Oil who is now a professor at the University of California at Berkeley, is "a key part of the crime scene."
Since the disaster began in April, the public has been bombarded with detailed explanations about how the "shear ram" valve on the blowout preventer (BOP) was supposed to slice through the drill pipe in an emergency and shut off the well. That it failed is clear enough.
But why it failed remains anything but clear. All the digging through documents, all the mountains of testimony before Congress and federal panels have led only to conjecture about possible causes of failure. Careful dissection of the BOP and a look inside the steel jaws that did not close now appear to be the only ways to learn what happened.
"The BOP is this key piece of physical evidence – perhaps the last best hope for putting the pieces of the puzzle of the Deepwater Horizon together," says John Rogers Smith, associate professor of petroleum engineering at Louisiana State University.
Thad Allen, the Gulf national incident commander, on Thursday gave the go-ahead for BP and Transocean, the drill rig operator, to replace the Deepwater Horizon's BOP with another and to bring the failed unit to the surface. But he warned BP that the BOP must be treated carefully to preserve evidence.
"Each procedure should recognize and preserve the forensic and evidentiary value of the BOP and any material removed from the BOP," he wrote in Thursday's directive to BP Chief Managing Director Bob Dudley. Along those lines, Justice Department investigators are now hunting for blowout preventer specialists who could conduct a forensic examination of the unit, one source told the Monitor.
The BOP may be the last best chance to find a "smoking gun" that tells investigators whether the blowout was a result of human error, mechanical failure, bad maintenance, faulty procedures – or a combination of those, industry experts say.