Datasets associated with investigating the potential for beneficial reuse of produced water from oil and gas extraction outside of the energy sector.

The data in this report are associated with https://doi.org/10.1016/j.scitotenv.2020.137085[4] and include data on water volumes and water quality related to the major unconventional oil and gas plays in the U.S. The data include volumes of water co-produced with oil and gas production, county-level estimates of annual water use volumes by various sectors, including hydraulic fracturing water use, and the quality of produced water. The data on volumes of produced water and hydraulic fracturing water volumes were obtained from the IHS Enerdeq and FracFocus databases. Water use in other sectors was obtained from the U.S. Geological Survey water use database. Data on produced water quality were obtained from the USGS produced waters database.

Can we beneficially reuse produced water from oil and gas extraction in the U.S.?

There is increasing interest in beneficial uses of large volumes of wastewater co-produced with oil and gas extraction (produced water, PW) because of water scarcity, potential subsurface disposal limitations, and regional linkages to induced seismicity. Here we quantified PW volumes relative to water demand in different sectors and PW quality relative to treatment and reuse options for the major U.S. shale oil and gas plays. PW volumes from these plays totaled ~600 billion liters (BL, 160 billion gallons, Bgal) in 2017. One year of PW is equal to ~60% of one day of freshwater use in the U.S. For these plays, the total irrigation demand exceeded PW volumes by ~5× whereas municipal demand exceeded PW by ~2×. If PW is reused for hydraulic fracturing (HF) within the energy sector, there would be no excess PW in about half of the plays because HF water demand exceeds PW volumes in those plays. PW quality can be highly saline with median total dissolved solids up to 255 g/L in the Bakken play, ~7× seawater. Intensive water treatment required for PW from most unconventional plays would further reduce PW volumes by at least 2×. Desalination would also result in large volumes of salt concentrates, equivalent to ~3000 Olympic swimming pools in the Permian Delaware Basin in 2017. While water demands outside the energy sector could accommodate PW volumes, much lower PW volumes relative to water demand in most regions would not substantially alleviate water scarcity. However, large projected PW volumes relative to HF water demand over the life of the play in the Permian Delaware Basin may provide a substantial new water source for beneficial use in the future. Large knowledge gaps in PW quality, lack of appropriate regulations, and economic factors currently preclude beneficial uses outside the energy sector in most regions.

Will Water Issues Constrain Oil and Gas Production in the United States?

The rapid growth in U.S. unconventional oil and gas has made energy more available and affordable globally but brought environmental concerns, especially related to water. We analyzed the water-related sustainability of energy extraction, focusing on: (a) meeting the rapidly rising water demand for hydraulic fracturing (HF) and (b) managing rapidly growing volumes of water co-produced with oil and gas (produced water, PW). We analyzed historical (2009-2017) HF water and PW volumes in ∼73 000 wells and projected future water volumes in major U.S. unconventional oil (semiarid regions) and gas (humid regions) plays. Results show a marked increase in HF water use, and depleting groundwater in some semiarid regions (e.g., by ≤58 ft [18 m]/year in Eagle Ford). PW from oil reservoirs (e.g., Permian) is ∼15× higher than that from gas reservoirs (Marcellus). Water issues related to both HF water demand and PW supplies may be partially mitigated by closing the loop through reuse of PW for HF of new wells. However, projected PW volumes exceed HF water demand in semiarid Bakken (2.1×), Permian Midland (1.3×), and Delaware (3.7×) oil plays, with the Delaware oil play accounting for ∼50% of the projected U.S. oil production. Therefore, water issues could constrain future energy production, particularly in semiarid oil plays.

An Improved Approach for Forecasting Ecological Impacts from Future Drilling in Unconventional Shale Oil and Gas Plays.

Directional well drilling and hydraulic fracturing has enabled energy production from previously inaccessible resources, but caused vegetation conversion and landscape fragmentation, often in relatively undisturbed habitats. We improve forecasts of future ecological impacts from unconventional oil and gas play developments using a new, more spatially-explicit approach. We applied an energy production outlook model, which used geologic and economic data from thousands of wells and three oil price scenarios, to map future drilling patterns and evaluate the spatial distribution of vegetation conversion and habitat impacts. We forecast where future well pad construction may be most intense, illustrating with an example from the Eagle Ford Shale Play of Texas. We also illustrate the ecological utility of this approach using the Spot-tailed Earless Lizard (Holbrookia lacerata) as the focal species, which historically occupied much of the Eagle Ford and awaits a federal decision for possible Endangered Species Act protection. We found that ~17,000-45,500 wells would be drilled 2017‒2045 resulting in vegetation conversion of ~26,485-70,623 ha (0.73-1.96% of pre-development vegetation), depending on price scenario ($40-$80/barrel). Grasslands and row crop habitats were most affected (2.30 and 2.82% areal vegetation reduction). Our approach improves forecasts of where and to what extent future energy development in unconventional plays may change land-use and ecosystem services, enabling natural resource managers to anticipate and direct on-the-ground conservation actions to places where they will most effectively mitigate ecological impacts of well pads and associated infrastructure.

Projecting the Water Footprint Associated with Shale Resource Production: Eagle Ford Shale Case Study.

Production of oil from shale and tight reservoirs accounted for almost 50% of 2016 total U.S. production and is projected to continue growing. The objective of our analysis was to quantify the water outlook for future shale oil development using the Eagle Ford Shale as a case study. We developed a water outlook model that projects water use for hydraulic fracturing (HF) and flowback and produced water (FP) volumes based on expected energy prices; historical oil, natural gas, and water-production decline data per well; projected well spacing; and well economics. The number of wells projected to be drilled in the Eagle Ford through 2045 is almost linearly related to oil price, ranging from 20 000 wells at $30/barrel (bbl) oil to 97 000 wells at $100/bbl oil. Projected FP water volumes range from 20% to 40% of HF across the play. Our base reference oil price of $50/bbl would result in 40 000 additional wells and related HF of 265 × 109 gal and FP of 85 × 109 gal. The presented water outlooks for HF and FP water volumes can be used to assess future water sourcing and wastewater disposal or reuse, and to inform policy discussions.