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Constraints on Upward Migration of Hydraulic Fracturing Fluid and Brine

July 29, 2013
By Samuel Flewelling and Manu Sharma

Recent increases in the use of hydraulic fracturing in the production of oil and natural gas from shales and tight sandstone formations have raised concerns regarding potential environmental effects associated with predictions of upward migration of

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Recent increases in the use of hydraulic fracturing in the production of oil and natural gas from shales and tight sandstone formations have raised concerns regarding potential environmental effects associated with predictions of upward migration of hydraulic fracturing fluid and brine.

Some recent studies have suggested that such upward migration can be large and that timescales for migration can be as short as a few years. In this article, we discuss the physical constraints on upward fluid migration from black shales such as the Marcellus, Bakken, and Eagle Ford, to shallow aquifers, taking into account the potential changes to the subsurface brought about by hydraulic fracturing.

Hydraulic fracturing affects a very limited portion of the entire thickness of the overlying bedrock and therefore, is unable to create direct hydraulic communication between black shales and shallow aquifers via induced fractures.

 As a result, upward migration does not appear to be physically plausible. Unrealistically high estimates of upward flow are the result of invalid assumptions about hydraulic fracturing and the hydrogeology of sedimentary basins, and upward migration of these fluids would take hundreds of millions of years to reach groundwater resources.

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Energy