Events

Speaker:  Dr. Bridget Scanlon, Senior Research Scientist at the Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin

Title of Seminar: “Water Issues Related to Transitioning from Conventional to Unconventional Oil Production in the Permian Basin”

Abstract: Expanding oil production from conventional to nearby unconventional reservoirs in the Permian Basin using hydraulic fracturing (HF) can markedly increase water risks in the basin. Here we explore water risks related to HF water demands and produced water (PW) management based on detailed well by well analysis in the semiarid Permian Basin. HF water demands totaled ~2×109 barrel (bbl) with increasing water use/well by ~10 times and per foot of lateral by ~7 times (2005 – 2015). PW (44×109 bbl) totals about 20 times HF water, ~90% from conventional reservoirs. However, the large volumes of PW from conventional wells (13 bblPW/bbl oil) is injected into pressure-depleted reservoirs for enhanced oil recovery. In contrast, lower PW volumes (~3 barrels [bbl] water/bbl oil) from unconventional reservoirs cannot be reinjected into the low permeability reservoirs directly but is disposed into non-producing horizons. Disposal of PW into non-producing horizons locally over-pressures some geologic intervals and increasing disposal near the basement (Ellenburger) could induce seismicity. PW from unconventional wells can be injected into the reservoir indirectly by reusing it for HF for the next set of wells and recent advances in fluid chemistry for hydraulic fracturing accommodate direct reuse of PW. There is sufficient PW being disposed to meet increasing HF water needs throughout most of the Permian Basin. Reuse of PW would reduce water risks by reducing scarcity concerns for HF and PW management issues related to over-pressuring and potential induced seismicity. Analysis of water issues in the Permian Basin should provide valuable insights for other conventional reservoirs that are transitioning to increasing unconventional production.

Biography:   Bridget Scanlon is a Senior Research Scientist at the Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin. She has worked at the Univ. of Texas since 1987. Her current research focuses on the interdependence of water and energy, focusing on water quantity aspects. She also works on broader issues related to water resources within the context of climate extremes using ground-based and satellite data. She is an Associate Editor at Water Resources Research and at Environmental Research Letters and has authored ~ or co-authored many publications. Dr. Scanlon is a Fellow of the American Geophysical Union and the Geological Society of America and a member of the National Academy of Engineering.