aturday, July 10, 2010
The Missing Link in the Oil Leak Story: The Second Section of Drill Pipe
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 won dered 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.
Video images of the riser when it was cut in early June clearly showed the two pipes, raising speculation on blogs. 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.
The second section of drill pipe is key to the oil leak story for two reasons.
First, as the Times-Picayune notes, it has contributed to problems in partially capping the leak and capturing more oil.
Second, the source of the second segment is key to determining the condition of the oil well beneath the subfloor. I hope that Simmons and Bea are proven wrong, and that the second drill pipe came from (1) a collapse of pipe above the blowout preventer or (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).
If they are right, drilling the relief wells will be a lot more challenging.