Gulf Gusher Dwarfs Previous Estimates, BP Will Inject Junk to Plug It
HOUSTON, Texas, May 13, 2010 (ENS) – Scientific analysis of a new video released Wednesday by BP shows oil and gas spilling from the broken Deepwater Horizon wellhead on the the Gulf of Mexico seafloor at a much higher rate than previously estimated.
The analysis by Purdue mechanical engineering professor Steve Wereley obtained by National Public Radio found that the rate of flow could range between 56,000 and 84,000 barrels a day – at least 10 times the Coast Guard’s earlier, widely quoted, estimate of 5,000 barrels a day.
NPR also cited a separate analysis by Eugene Chiang, an astrophysics professor at the University of California-Berkeley, who calculated the rate of flow within a range from 20,000 barrels a day to 100,000 barrels a day.
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Oil and gas escaping from the wellpipe broken off when the Deepwater Horizon oil rig exploded and sank in April. May 12, 2010. (Image courtesy BP) |
BP officials have repeatedly said there is no way to measure the rate of flow from the broken pipe.
“There’s just no way to measure it,” said Kent Wells, a BP senior vice president, in a technical briefing Monday.
But calculations by Professor Ian MacDonald, a biological oceanographer at Florida State University, show an average flow rate of about 26,000 barrels (more than one million gallons) per day is spewing from the damaged well, five times more than the original estimate.
MacDonald’s research suggests that as much as 13 million gallons of oil was spilled into the Gulf of Mexico between April 20, the date the Deepwater Horizon exploded and caught fire, and May 7.
By comparison, the official estimate for the 1989 Exxon Valdez spill in Alaska is 11 million gallons.
MacDonald used U.S. Coast Guard aerial overflight maps of the oil slick to estimate the total surface area of the oil spill, then applied standard guidelines to measure the thickness of the oil. By combining the two, he was able to provide a revised estimate showing that the oil spill is far worse than originally believed.
While BP’s first effort to capture the spilling oil in a containment dome for transfer to a ship at surface was unsuccessful last weekend, Wells and BP chief executive Tony Hayward say they are confident that the techniques they are planning to employ starting at the end of this week will shut off the flow of oil.
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BP chief executive Tony Hayward briefs reporters, May 10, 2010 (Photo courtesy BP) |
Hayward said, “We now have in Houston, a global industry effort. There are companies here from around the world. There is every major science and technology organization in the United States in this building today working on this problem. The learning from this will be very extensive and it will inform what needs to happen in the future.”
At the request of President Barack Obama, Interior Secretary Ken Salazar and Energy Secretary Steven Chu traveled to Houston this week to meet with Energy Department and national lab staff, industry officials and other engineers and scientists involved in finding solutions to cap the flow of oil and contain the spill.
The first containment dome, 40 feet high and weighing 100 tons, was lowered on May 8, but it plugged up with icy gas hydrates that prevented the oil from flowing up pipes into the waiting ship, so now engineers will try a much smaller four by five foot containment dome called a “top hat,” said Wells.
“We’re going to have it all connected up to the the drill ship when we put it over,” Wells explained. “It will be trickier operating the smaller one, but we will make that work. We expect to have it in operation by the end of the week.”
At the same time, Wells said, BP engineers are working on plugging the pipe with junk in a technique they’re calling the “junk shot”
First, they had to retrieve a dysfunctional control pod attached to the blowout preventer, the complex series of valves at the wellhead that failed to shut off the well when it blew out on April 20.
Working with remotely operated vehicles, the control pod was brought to the surface and all the electronics were refurbished, Wells explained. When it’s time to try plugging the well with a junk shot, “We will take it back down and put it back in place so we can operate the choke and kill lines,” said Wells.
Electric signals from the control pod will produce hydraulic action to operate those choke and kill lines, one on each side of the blowout preventer.
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BP vice president Kent Wells conducts a technical briefing with a model of the blowout preventer. (Photo courtesy BP) |
“We will arrange it so that we can bring pipe from the surface down into a manifold and connect into the the choke and kill lines,” Wells said. “With that ability to pump material in there and ability to control the valves on it we believe we can successfuly do the junk shot.”
The junk that will be pumped down the well is an odd mixture of things like golf balls, tires, and tennis balls, said Wells. “It’s absolutely the truth. We’re trying to get a mix of different sizes of materials of different sizes that will wedge into this and hold.”
“We’ll inject the junk shot, it will go into the blowout preventer. Ideally, it’ll plug it as soon as we do it, but we can change the recipe and try again until it is plugged,” Wells explained. “We will follow immediately with drill mud.”
Wells said BP will have “huge pumping facilities at the surface. We will push the oil and gas back into the reservoir and it will be killed.”
“As soon as we’ve done that,” said Wells, “we will follow it with cement and we will permanently abandon this well.” He said BP is “not worried about losing this well, we’re going to fill it full of cement.”
These plans will be carried out over the next two weeks, Wells said.
He said this technique has been used all over the world, particularly in Kuwait to stop the oil fires ignited during the First Gulf War, but it has never been used at the current depth of 5,000 feet beneath the surface.
In case none of these plans plug the broken wellhead, BP is drilling relief wells to divert the flow of oil.
Hayward said, “We’re drilling two relief wells. We believe this will assure ultimate success. The second relief well is being drilled in case we have problems with the first one.”
While the first relief well has already reached 9,000 feet beneath the seafloor, the original test well that is now spewing oil into the gulf was drilled to a depth of 18,000 feet. Completion of the first relief well is expected to take roughly 90 days.
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