With fracking, millions of gallons of water and sand, as well as certain chemicals, are pumped underground — typically a mile or more below the surface — to break apart the rock and release the gas. The pressure causes the rock layer to crack, and the fissures are held open by the sand particles to allow the natural gas to flow.
Fracking has become a critical process in large part because of improvements in other techniques, such as horizontal drilling and 3-D seismic imaging, which have helped make unconventional gas extraction more feasible.
According to a report by IHS Global Insight, unconventional gas activity accounted for 53 percent of natural gas production in the United States in 2010. It’s expected to grow to 79 percent of production by 2035.
But unconventional well drilling is more energy intensive than it is for conventional wells. Robert Jackson, professor of global environmental change at Duke University, says because gas flows more easily in conventional wells, it usually isn’t necessary to drill down as far as is necessary in shale.Page 2 of 6 | Prev Page | Next Page