Fracking and its Risks By the 1970s America’s energy industry seemed to be in terminal decline. The oil majors had long ago gone abroad in search of richer fields. But a technique invented in the 1940s and adapted decades later by George Mitchell, a Texan oil man, could unlock the oil and gas reserves trapped in shale rock. Mr Mitchell found that by injecting water, sand and chemicals into the ground at high pressure he could fracture the rock and create pathways for the trapped oil and gas to escape. Light regulation and government subsidies have seen fracking take off in America. Shale beds now produce a quarter of the country’s natural gas, up from only 1% in 2000. By last year the price of gas in America had fallen to about a quarter of that in Europe and a sixth of that in Asia, though it has since risen. Fracking is not without risk. As gas rises to the surface it can escape into drinking water. Recent research published in Proceedings of the National Academy of Sciences, on the impact of drilling in the Marcellus Shale, which stretches from north-eastern Pennsylvania to southeastern New York, found that four-fifths of nearby wells contained methane and that concentrations of gas in the water in nearby homes were far higher than in those further away. Poorly sealed well casings could be to blame. But similar studies of other shale beds have found no methane in nearby wells. Some worry that the subterranean fractures could cause earth tremors: a study linked fracking to small tremors in northern England in 2011 but there is almost no evidence of such tremors in America, where many thousands of wells have been sunk.
Posted on: Wed, 21 Aug 2013 09:59:28 +0000
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