BP delayed test out of concern for wellbore status-exec
HOUSTON | Wed Jul 14, 2010 12:58pm EDT
HOUSTON July 14 (Reuters) - BP Plc (BP.L) (BP.N) and U.S. government scientists delayed a key pressure test on the gushing Gulf of Mexico oil well late on Tuesday because of concerns that the test could damage the wellbore, a BP executive said on Wednesday.
"There were a couple of other concerns around ways flow could escape and we needed to go examine those before we proceeded," Doug Suttles, BP chief operating officer of exploration and production, told CNN.
(Reporting by Kristen Hays and Chris Baltimore, Editing by Sandra Maler)
The 36" conducter casing is 2" thick and extends 254' into the sea floor. Inside of the conductor casing the next string of casing is the 28" and is 3/4" thick and extends 1150' into the sea floor. My concern is the 2 pieces of drill pipe that were inside the cut off piece of marine riser. Only 1 piece of drill pipe was expected. If it was actually 2 pieces of drill pipe that are 6 5/8" OD with the tool joint connector being larger, I would suspect that as once the drill pipe broke and parted and fell, somewhere within the inside casing which is the tapered 9 7/8" x 7" it is ruptured.
The testing delay was announced with little explanation late Tuesday night by Coast Guard Adm. Thad Allen, the federal oil-spill response commander.
Wells, in a morning press conference, said the "24-hour timeout" was ordered due in part to questions about whether the test would be able to determine a key issue: Whether the oil, if leaking, was coming from a shallow or a deep part of the well.
"What we want to do is avoid that oil is being put out in the shallow environment," Wells said. "There's always the potential, remote as it might be, that it could breach up to the surface."
The threat of a crater forming on the sea bed around the well head -- with oil flowing from multiple points -- would be a potentially catastrophic scenario that would make containing the oil extremely difficult.
But according to Darryl Bourgoyne, director of the petroleum research lab at Louisiana State University, leaks deep in the well may not be much of a problem--so long as it was so deep that "the fluid would stay in the subsurface, and cratering wouldn't be a risk."
The permanent fix for the well, which has been leaking up to 60,000 barrels of oil per day since an April 20 rig blowout, will come when it is intersected far beneath the earth's surface by one of two relief wells underway. The closest of those wells, currently at 17,840 feet in length, is scheduled to plug the faulty well with mud and concrete sometime in mid-August.
Wells said that work on that well was delayed until the integrity test could be completed -- which puts a permanent solution another one to two days behind schedule.
Actually, BP's "concern" was expressed by halting the relief drilling while they tested casing integrity.
The gov't halt makes zero sense. It's impossible to test the integrity of anything until the flow is restricted. BP's plan to do this slowly over a couple of days was a reasonable approach.
Don't forget that the pinched riser had been restricting the flow until it was removed. In a sense, partially closing the valves on the stack is returning to where they were day 1 after Deepwater Horizon sank.
Halting the testing doesn't accomplish a thing.
When the entire weight of the Deepwater Horizon rig settled and sank on 5,000 feet of 22 inch heavy wall riser pipe that was still conected to the well head would it be unreasonable to suspect that there may have been some stresses induced in the sub-sea well casing?
Remember that riser pipe was twisted like spaghetti.