BASELINE MONITORING OF GROUNDWATERS IN AN AREA OF ACCELERATING SHALE GAS DEVELOPMENT IN NORTH CENTRAL WEST VIRGINIA

One of the main challenges associated with Marcellus shale gas development is to ensure proper management and disposal of flowback water produced as a result of hydraulic fracturing of gas wells. The flowback water consists of a mixture of returned fracking fluids and highly saline formation brines. As a result, improper management or disposal of this flowback can potentially contaminate the fresh surface waters and groundwaters of the area. To better assess any detrimental effect on water quality, there is need to understand the natural geochemical variations prior to the rapid expansion of gas drilling in the area.

This study focuses on documenting the baseline geochemical characteristics of groundwaters in different formations lying stratigraphically above the Marcellus formation. 41 groundwater well sites in north central West Virginia were sampled with the USGS Water Science Center of West Virginia. These private and public sampling locations were chosen from within the USGS database and represent different formation aquifers with differing well depths. Geochemical data was obtained for major cations and anions, dissolved gas concentrations of methane, oxygen and hydrogen isotopic compositions of water (δ¹⁸O_H2O and δD_H2O), carbon isotopic compositions of dissolved inorganic carbon (δ¹³C_DIC), sulfur and oxygen isotope compositions of dissolved sulfate (δ³⁴S_SO4 and δ¹⁸O_SO4) and carbon and hydrogen isotope compositions of dissolved methane (δ¹³C_CH4 and δD_CH4). Field parameters of temperature, conductivity, pH, dissolved oxygen, turbidity, and oxidation reduction potential were also collected. We hypothesize that the baseline variations of stable isotopes can be used in conjunction with other geochemical parameters to identify groundwater aquifers that have received significant contribution from frac flowback waters.