Monday, July 12, 2010

A Key Piece in the Oil Leak Story: Two Sections of Drill Pipe Lodged in the Blowout Preventer

by Washington's Blog

On June 30th, I noted that the Department of Energy had found that there were two section of drilling pipe lodge in the blowout preventer.

Yesterday, the Times-Picayune gave an update on this story, which includes competing interpretations about where the second section came from and what that means for the relief wells:

For the first time Friday, the Coast Guard and BP acknowledged that a mysterious second pipe, wedged next to the drill pipe in what remains of the Deepwater Horizon's riser, is fouling up the works where the well is spewing hundreds of millions of gallons of crude oil into the Gulf of Mexico.

"We used a diamond saw and we got inside. We found there was actually two sets of drill pipe there," said retired Adm. Thad Allen, the top U.S. Coast Guard official overseeing the response to America's worst-ever oil spill.


It "presumably fell down beside it as a result of the explosion and the riser pipe being bent over," Allen said. He noted that the second pipe does not have oil shooting from it.

BP officials said late Friday that they believe the second pipe is drill pipe. Pictures show it is similar in diameter to the known drill pipe.

While Allen said he believes the second pipe fell from above, some experts have advanced another explanation. They believe poorly cemented casings -- tubes that are supposed to form solid walls down thousands of feet of the well bore -- may have been dislodged by the blast of natural gas that shot up out of the well and above the sea floor.


The idea that a loose pipe shot up from deeper in the well and prevented the shear ram from closing has been espoused by such experts as oil industry investment banker Matt Simmons and Bob Bea, a University of California at Berkeley engineer leading a scientific investigation into the blowout [Bea is an expert in offshore drilling and a high-level governmental adviser concerning disasters]. But others have wondered if the mystery pipe isn't just a section of the same drill pipe that came loose, or even a pipe that fell down the riser from the rig 5,000 feet above.

The source of the second segment is key to determining the condition of the oil well beneath the seafloor. If Simmons and Bea are proven right, drilling the relief wells will be a lot more challenging.

Therefore, I hope they are wrong, and that the second drill pipe came from:

(1) a collapse of pipe above the blowout preventer;


(2) a miscellaneous segment of drilling pipe (drilling pipe is temporarily used in drilling a well, and is not the same as well casing or even well lining, which are permanently installed to support the well).

The second section of drill pipe is key to the oil leak story for another reason. As the Times-Picayune notes, it has contributed to problems in securely capping the leak from the point where it's leaking so that more oil can be captured:

The presence of two pipes could have also contributed to BP's failure to make a clean cut on the riser when securing the existing containment dome, inhibiting its ability to collect the maximum amount of oil.


Allen said the second pipe also led to a jagged cut on the larger riser pipe, forcing the response team to use the loose cap with a rubber seal. And now, the two pieces are forcing the team to spend several days tying them together and clearing the way for a new, hopefully more solid connection.

Finally, the two sections of drill pipe are important because they may have been one of the reasons that the blowout preventer failed in the first place.

As the Times-Picayune notes:

Some experts say a second piece of drill pipe in the riser could have prevented shear rams on the rig's blowout preventer from sealing the well and permanently cutting off the flow of oil after the April 20 explosion.

Even if it turns out that this is one of the causes of the BOP's failure, it might not be the only cause.

As I pointed out in May:

[Mike Williams, the chief electronics technician on the Deepwater Horizon, and one of the last workers to leave the doomed rig] claimed that the blowout preventer was then damaged [Several weeks before the Gulf oil explosion] when a crewman accidentally moved a joystick, applying hundreds of thousands of pounds of force. Pieces of rubber were found in the drilling fluid, which he said implied damage to a crucial seal. But a supervisor declared the find to be “not a big deal”, Mr Williams alleged.


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