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David Pettit’s Blog

Turns out blowout preventers may not prevent blowouts

David Pettit

Posted March 25, 2011 in Health and the Environment, Living Sustainably, Moving Beyond Oil

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On March 23, 2001, the federal Bureau of Ocean Energy, Management and Regulation (BOEMRE) released the results of a technical study of the blowout preventer that failed to stop the BP Deepwater Horizon blowout nearly a year ago.  I was shocked by the results, as were many others

A blowout preventer is supposed to be the last, fail-safe defense against a well blowout.  According to the Dallas News

Three years ago, Cameron senior manager Melvyn Whitby wrote about the importance of deepwater blowout preventers in Drilling Contractor magazine:  When "the BOP is called on to function in an emergency situation, it is the main barrier protecting human life, capital equipment and the environment. Therefore, it must function without fail."

But the Deepwater Horizon blowout preventer, manufactured by Cameron, did fail.  It failed because the pressure of the escaping oil and gas buckled the drill pipe and pushed it off-center so that the jaws of the blowout preventer’s shear rams, which are supposed to cut and seal the drill pipe, jammed and could not close.  In my view, this is a fundamental design defect in the design of the Cameron-style blowout preventers, which are widely used in deepwater exploration.  We now know that there is a critical failure mode in these devices which has not been designed against.

This shows that the blowout preventers are not fail-safe, and do not meet the standards that Cameron’s Mr. Whitby set out.  Indeed, BOEMRE knows that blowout preventers are not fail-safe:  studies that BOEMRE’s predecessor did or commissioned show that these devices do fail on occasion.  Not always – but from the safety standpoint, sometimes is unacceptable.

Where does this leave us?  BOEMRE has permitted five new or resumed deepwater wells in the last five weeks, each of which relies on a blowout preventer as a last line of defense against a blowout.  In my view, none of those projects is safe. 

This is not to say that BOEMRE has allowed pre-oil spill looseness in permitting to continue.  Here is a short list of the reforms that BOEMRE has taken since Director Bromwich took office.  BOEMRE has issued a new drilling safety rule that includes requirements for blowout preventers, and a new workplace safety rule.  New guidance has been issued requiring oil companies to calculate their worst-case discharge and to show how they can and will contain that worst-case situation.  But none of those positive steps was taken in the knowledge that there is a critical design flaw in the blowout preventers. 

In my view, it is unwise and unsafe to permit a single new well until the blowout preventers used are re-designed to eliminate the failure mode that crippled the Deepwater Horizon device, and tested in realistic operating conditions.  And by “realistic” I mean with high-pressure oil and gas flowing through a drillpipe inside the device.  Here is an unbelievable quote from the Wall Street Journal article on the BOEMRE technical report:  “In testimony before the presidential commission investigating the spill last year, Bill Ambrose, a Transocean executive, said blowout preventers weren't designed to cut off a flowing well.” 

Oh really, Mr. Ambrose?  So in the view of Transocean (who owned and operated the Deepwater Horizon rig), the blowout preventer is not designed to prevent a blowout?  How safe can oil wells be considered while blowout preventers have this fundamental flaw?

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Switchboard is the staff blog of the Natural Resources Defense Council, the nation’s most effective environmental group. For more about our work, including in-depth policy documents, action alerts and ways you can contribute, visit NRDC.org.

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