Engineer Explains Why Hydraulic Fracturing in the Marcellus Shale is Safe
The Energy Collective (Feb 23)
Shale Gas and Drinking Water
In an article posted on The Energy Collective website, Geoff Styles, who has a degree in chemical engineering (U.C. Davis) and worked for Texaco for 22 years, in addition to working for NASA, explores just what hydraulic fracturing is, how it’s done, and why it’s safe, particularly in the Marcellus Shale deposit. It is an extremely well written and enlightening article—please read it!
Here is a brief extract:
[F]or the purposes of this discussion let’s take a quick look at one of the shale regions at the heart of this controversy, the Marcellus Shale in the Appalachian region of New York, Pennsylvania and the Virginias. In the course of my research I ran across a handy document on groundwater from Penn State. Aside from surface water (lakes, rivers and streams), it identifies the various aquifers in Pennsylvania by type in Figure 4. The key fact from the perspective of fracking safety is that the deepest of these aquifers lies no more than about 500 ft. below the surface, and typically less than a couple of hundred feet down. By contrast, the Marcellus Shale is found thousands of feet down–in many areas more than a mile below-ground–with a thickness of 250 feet or less. In addition, the gas-bearing layers are sealed in by impermeable rock, or the gas would eventually have migrated somewhere else. In other words, the shale gas reservoirs are isolated by geology and depth from the shallower layers where our underground drinking water is found.
He covers many other issues, including the relatively SMALL amount of water used to frack a well with horizontal drilling—compared with water used in a “traditional” oil or gas well. And how the aquifer is protected when the drilling begins, before any water and chemicals are pumped into the well.
Bottom line?
Thus, whether intentionally or as a result of a basic misunderstanding of how this technology works, we are being presented with a false dichotomy concerning shale gas and fracking. The real choice here isn’t between energy and drinking water, as critics imply, but between tapping an abundant source of lower-emission domestic energy and what looked like a perpetually-increasing reliance on imported natural gas just a few years ago.
Well said Mr. Styles. Well said.
