How to stop the BP oil spill: What else can be tried now?
BP has failed to manually shut the blowout preventer, and it could take three months to drill a relief well. Before then, BP will try to put a giant hood over the leaking wellhead, or perhaps even install a second preventer. But no short-term options have a proven track record to stop an oil spill.
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But the team experienced a range of problems that eventually led them to jettison the idea. In effect, the system was too small, based on initial, ultimately incorrect estimates of the amount of oil and gas leaking from the well. In addition, the team had a tough time positioning the sombrero over the wellhead; sea-floor wreckage from the blowout impeded the work. And the quantities of oil, gas, and water were far larger than the team was prepared to handle.Skip to next paragraph
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The containment covers technicians are building for this event look more like oversize range hoods for kitchen stoves, Hayward said. These 74-ton steel and concrete structures will aim to guide oil and any gas up toward a pipe at the peak and into waiting ships for separation.
If the containment covers are big enough, and if technicians can bring the oil and water to the surface and separate them adequately – either naturally or by using powerful pumps – the covers "might diminish the amount of oil that gets into the environment by some significant percentage," he says.
This will be the first time anyone has tried the approach in such deep water with its enormous pressure. The Ixtoc blowout, which ultimately lasted nine months, occurred in 165 feet of water.
And if that doesn't work?
One other option exists – stacking another blowout preventer on top of the faulty one. But while that's been done on land, it hasn't been done underwater with a flowing well, says John Smith, a petroleum engineer at Louisiana State University in Baton Rouge.
"A major consideration has to be that you don't want to make the problem worse," if something goes wrong while trying to install the added blowout preventer, he says.
Meanwhile, researchers have been experimenting with improvements to blowout protectors, which rely on hydraulics to shut off a well. Engineers at the University of Houston have been experimenting with blowout preventers that rely on so-called smart metal alloys to open and shut them. These alloys contract when heated, then return to their initial shape when cooled.
The team designed cables from these alloys, and using electric currents, induced the cables to open and close off a drill hole. The team estimates that a scaled-up version could shut off a highly pressurized well pipe within about 15 seconds of being triggered by special sensors.
At the least, the approach represents a potential back-up to existing blowout preventers, says Gangbing Song, who led the design team.