IS WATER SCARCITY AN ISSUE FOR HYDRAULIC FRACTURING IN SEMIARID REGIONS?

Because ~40 – 50% of shale plays are located in semiarid regions globally, there is concern about water scarcity limiting energy production in these regions. Water scarcity is defined as water demand exceeding supplies; therefore, scarcity depends on the quantification of water demand and definition of water supplies. Here we evaluated potential water scarcity concerns by comparing water demand relative to supplies using the Eagle Ford Shale Play as a case study. We quantified water use for all wells hydraulically fractured from 2009 through 2014. We estimated future water demand based on projected future well drilling and expected well completion practices, using estimated ultimate recovery for existing wells that considers changes in technology and oil and gas economics. We compared projected water demand over the next 20 years with estimated fresh and brackish water resources using data from regional modeling and water quality data from wells mostly in the prolific Carrizo Wilcox aquifer. Results show average water use of ~ 5 million gallons/well in the play area. Estimated potential freshwater supplies include ~1000 billion gallons from recharge over the next ~ 20 yr and ∼10,000 billion gallons from fresh groundwater storage. Non-freshwater sources include initial recoverable flowback water, which is ⩽5% of water use for hydraulic fracturing, limiting reuse/recycling. While operators report increasing use of brackish groundwater with estimated brackish groundwater storage of ~80,000 billion gallons, land-owner lease agreements often stipulate purchase of freshwater. Projected water demand for all sectors over the next 20 years is <5% of fresh and brackish groundwater storage in the aquifers at a square mile grid scale, with the exception of a couple of counties where irrigation water demand is high (~90% of total water demand). Therefore, with appropriate management, water availability should not physically constrain future shale energy production in the Eagle Ford play area if we consider both fresh and brackish groundwater supplies.