Monday, July 9, 2012

Hyrdraulic Fracturing and Groundwater: A Connection

Engineers and scientists at Duke University and Cal State (Pomona) have published a paper in the Proceedings of the National Academy of Sciences which confirms my long-stated belief that the industry certainly doesn't know everything about the effects of hydraulic fracturing of deep shale gas formations and possible impacts on shallow, drinking water aquifers.

This paper is not a smoking gun for condemning the burgeoning shale gas industry.  What is its value?  It shows that there is a mechanism for hydraulic connectivity between shallow drinking water aquifers and deep-lying shale gas formations.  The researchers found evidence of a "strong geochemical footprint" in salinized water in the Alluvium, Catskill and Lock Haven aquifers in northeastern Pennsylvania. The salts are chlorides of the s-block elements, alkali metals and alkaline earth metals. 

They speculate about the conditions that might provide a pathway for the salinization of the aquifers, but it is an educated supposition.  Shale formations with extraordinary hydrodynamic pressures and a natural pathway might cause migration into the lower pressure areas of the aquifers.  Where, how, and why this occurs at some locations and not others is unknown.

Results on methane gas migration are sketchy in this sample.

The authors conclude,"The occurrences of saline water do not correlate with the location of shale-gas wells and are consistent with reported data before rapid shale-gas development in the region.

The research is in this paper definitely shows that continuing research is needed, and that industry and regulators should work together with conservatism and caution in well head designs, drilling techniques, and documentation of geological characteristics of the formations, integrated with existing data about the aquifers.  There is indeed a way in which methane and brines could migrate into drinking water supplies. 

Because such damage would be prohibitive to mitigate, the industry should make sure that the shale gas boom is not a California gold rush or a replay of early wildcatting of oil wells in Western Pennsylvania.  Meanwhile, this paper is a small beginning and far from the last word.

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