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.
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. 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.
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.
If that's what happened, the piece of pipe would have gone into the blowout preventer, the 450-ton tower of valves and pistons that sits on top of the well head and is supposed to shut off the well in an emergency. The Deepwater Horizon's blowout preventer failed to cut through the pipe that ran through it, and subsequent efforts to shut the so-called shear rams using remote-control submarine robots also failed.
Preliminary investigations have shown that other questionable decisions and well-design choices precipitated the blowout of a well that had been considered a "nightmare" by BP engineers. But the blowout preventer was the last-ditch way to save the rig from the explosions that killed 11 men and eventually led to the interminable leak.
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. 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 Coast Guard's acknowledgement of the two metal tubes Friday -- and a subsequent reference by BP to its plans to tie the two pipes together as the company installs a new oil collection system over the shaved-off riser -- actually comes more than a month after the Department of Energy noted the existence of two pipes using special imaging technology. At the time, BP dismissed the Energy findings as "impossible" because only one pipe in sections was used for drilling, a Tribune News Service story reported last month.
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.
Business writers Rebecca Mowbray and Jaquetta White contributed to this report. David Hammer can be reached at firstname.lastname@example.org or 504.826.3322.