Comparison of Water Demand for Hydraulic Fracturing relative to Energy Production in Major U.S. Shale Oil Plays

Abstract:

There is considerable concern about the volume of water used for hydraulic fracturing to produce oil and gas from shale plays, particularly in semiarid regions with limited water supplies. Many analyses focus on water use per well because these data are readily available through the FracFocus database; however, a critical factor is the water use intensity (i.e., water use for hydraulic fracturing per unit of energy produced). In this study we quantified water use for hydraulic fracturing on a per well basis in the Eagle Ford, Permian Basin, and Bakken shale plays and compared these data with the volumes of oil produced to assess the water use intensity. Water demand per well varies markedly among the three plays. Controls on water use include type of well, length of lateral, frac fluid type, number of frac stages, and geology. For example, preliminary results indicate that less water is used for hydraulic fracturing per unit of energy in the Bakken relative to that in the other plays that was attributed to geologic differences. Most production is from the Middle Bakken, which is a tight sand/silt formation rather than shales as in the Eagle Ford and Permian plays. Water use per unit of energy production decreases with time after well completion, assuming a well is not refractured, and water use intensity estimates are based on estimated ultimate recovery. Quantifying water use in the Bakken is complicated because of additional water required after well completion to flush high levels of salts. Water use for oil production from unconventional reservoirs is within the lower range of that used for oil production from conventional reservoirs. Therefore, high levels of water use for hydraulic fracturing reflect increased energy production from unconventional reservoirs rather than higher water intensity.