August 1, 2011

Fracking Problems

by Dr. Robert Peltier, PE

By most estimates, natural gas is likely to become the dominant power generation fuel in the U.S. within perhaps a decade. The rapid growth in natural gas supplies follows advanced drilling techniques that can economically tap large shale gas reserves located deep beneath Earth’s crust. Unfortunately, it only takes one outlaw drilling company to frack it up for the rest of us.

To release natural gas trapped within the pore spaces of shale requires cracking the rock open. Horizontal drilling techniques allow a single well to perpendicularly intersect and travel through a shale formation. Hydraulic fracturing or “fracking” uses high-pressure water to induce further cracking of the shale around the bore hole, further increasing gas recovery. Sand and proprietary chemicals are also pumped into the pressurized well to prop open the minute shale fractures, allowing the gas to be captured, once the pressure on the well is relieved.

Enormous Gas Reserves

The Marcellus shale deposits—a mile beneath the Appalachian Basin, extending from southern New York through Pennsylvania, western Maryland, West Virginia, and eastern Ohio—now account for about one-third of U.S. natural gas reserves (2,552 Tcf). At the current rate of natural gas consumption (22.8 Tcf per year, 2009), that’s about 110 years of reserves. More good news: Geologists are predicting that larger shale gas formations below Marcellus may yield even greater quantities of gas in the future.

The number of wells and the rate of gas extraction are also growing exponentially. Gas wells tapping the Marcellus, producing 200 million cubic feet a day (cfd) in July 2008, were producing 1.4 billion cfd in July 2010. The number of shale gas wells drilled in Pennsylvania, for example, grew from only 27 in 2007 to 1,386 in 2010, according to the Pennsylvania Department of Environmental Protection.