It took months for BP to figure out how to stop oil from spewing out of the Deepwater Horizon site during last year’s infamous disaster, and not before the oil company tried everything from shooting junk down into the leaky pipe (the “junk shot”) to tapping Kevin Costner for advice. (Not that you would know any of this, based solely on its recent financial statements.) Next time around, BP might just want to try cornstarch.
That’s because researchers at Lawrence Livermore National Lab and Washington University recently discovered that cornstarch may be the key to a new mud recipe that could plug up oil leaks when shot into leaky pipelines (the “top kill” method). This is similar to the technique that BP used to plug its leak–the oil company pumped heavy mud into the wellbore until it finally stanched the oil flow. But the addition of cornstarch to the mud mix could be more effective. Here’s why it works.
BP’s top kill method failed for so long because the outgoing oil flow broke up the incoming stream of mud
into droplets that were swept out to sea with the oil. This is due to something called the the Kelvin-Helmholtz instability, which occurs whenever two fluids move past one another at varying speeds. The trick, then, is to find a fluid that flows like a thin fluid but resists instability by becoming hard under stress. Lawrence Livermore explains:
The Lab’s Peter Beiersdorfer, Edward Magee, and David Layne along with
Washington University’s Jonathan Katz created such a liquid, dubbed
shear-thickening by physicists, by using ordinary cornstarch. A
shear-thickening liquid like the cornstarch mixture can easily be poured
out of its container, but it thickens when shaken. Cornstarch mixed
with water acts like quicksand. If you sink in quicksand, it is
important to move slowly. The faster you move, the more the quicksand,
or in this case the cornstarch mixture, resists your movement. Fast
motion, like turbulence, is suppressed by the cornstarch.
The method was effective in lab experiments where the cornstarch was injected into a five-foot oil cylinder at speeds similar to those found in the BP oil disaster. The mixture resisted breaking up into droplets, just as the researchers suspected.
The real proving ground (or, water, really) will be in a large-scale oil disaster. But on the surface, at least, the research looks promising.
Update: Reader Benjamin Grynol reminds us that he originally proposed the cornstarch idea during our call for ideas to solve the BP oil disaster. Check it out here.