Using geophysical techniques to delineate a potential subsurface saline plume at a hydrocarbon production site near Graham, Texas

Groundwater contamination caused by hydrocarbon production activities has become increasingly common in Texas in the past few decades. This study investigates the use of Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES) to delineate a potential saline plume in a localized aquifer system in North Central Texas, where groundwater salinization abruptly elevated over the past three years (2010-2013). Various ERT and VES measurements are taken along the hypothetical plum flow path, which extends 300 m down-gradient from the oil and gas pumpjack, to differentiate the plume from background lithology. Both 1D and 2D inversions are shown in resistivity versus depth profiles. Results indicated that a high conductivity zone exists at 20 m from the pumpjack below 10 m depth, as well as an estimated water table at 40 m depth along the path. The aforementioned zone is interpreted as an upward flux driven by the pumping pressure from the leaky well casing at the pumpjack.