WASHINGTON — BP officials have moved to Tuesday the likely start for their next effort to permanently seal the Deepwater Horizon well in the Gulf of Mexico.
BP Senior Vice President Kent Wells said Friday that the delay by a day in the so-called "static kill" of the Macondo well was necessary because debris found at the bottom of a nearby relief well had to be removed before a final length of pipe could be put in place.
Wells said the debris consisted of 45 feet of rock and soil that had fallen into the bottom of the well after technicians were evacuated from the Deepwater Horizon site a week ago in preparation for Tropical Storm Bonnie. Wells said it was "not uncommon to find fill" in a well when it has been left unattended for a few days. "They're not perfect holes," he said.
He said technicians were removing the fill from the well and would then place and cement the last of the relief well's casing, a procedure that most likely would begin late Saturday. Once that work is completed, the static kill, which involves pumping drilling mud from a rig on the Gulf's surface into the well's blowout preventer, will begin.
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Wells described the static kill as a multi-step process that will start with what he called an "injectivity test" to determine the speed at which technicians will force heavy drilling mud into the well in hopes of driving the crude oil in the well back into the reservoir. Once the optimal speed is determined, technicians would pump mud in until pressure in the well has dropped to zero, indicating that the well has been contained.
At that point, technicians will dump cement into the well to permanently close it.
Wells didn't say how long the static kill would take. He said engineers believe the wellbore holds about 2,000 barrels of oil, or about 84,000 gallons. BP has 12,000 barrels of drilling mud standing by for the procedure, he said.
The goal is to force all of the oil back into the reservoir 13,000 feet below the sea floor in what is known as a "bullhead kill." Each gallon of drilling mud weighs 13.2 pounds. A gallon of oil weighs about seven pounds.
Wells said that engineers now think the Macondo wellbore wasn't seriously damaged in the April 20 blowout that set the Deepwater Horizon drilling rig aflame, killed 11 workers and sent millions of gallons of crude pouring into the Gulf.
He said the slow increase in pressure detected in the well since a containment cap sealed it on July 15 had persuaded scientists that there were no leaks. The pressure Friday was 6,961 pounds per square inch; when the cap was placed, the pressure was slightly above 6,700 psi.
Even if the static kill successfully forces the oil back into the reservoir, Wells said BP would complete the relief well, which has been under way since May 2 and was long touted as the only way to permanently close the Macondo well.
Wells said technicians drilling the relief well would probably be in position to try to intercept the Macondo well on Aug. 11 or 12 — dates that underscored how critical the containment cap now sealing the well has been to easing the crisis.
Wells said that killing the Macondo well with the relief well might require as much as three weeks after the intercept — a timetable that would've had oil spewing from the well until September, had the current containment cap not been successful.
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