ESTIMATING THE SUPPLY OF FRESH AND BRACKISH GROUNDWATER FOR HYDRAULIC FRACTURING IN THE PERMIAN BASIN OF WEST TEXAS

The objective of this study is to assess the volume of fresh and brackish groundwater in the Pecos Valley, Edwards-Trinity, Dockum, Rustler, and Capitan Reef Complex aquifers of the Permian Basin of West Texas and compare that to anticipated demand by hydraulic fracturing (HF) and other sectors over the coming decades. The depths, ages, screened intervals, water chemistry, pumped volumes and timing for HF, and locations of fractured wells were collected from databases hosted by the Texas Water Development Board (TWDB), Texas Commission on Environmental Quality (TCEQ), FracFocus, and University Lands. Total Dissolved Solids (TDS) and specific ion concentrations (Sodium, Calcium, Chloride, Sulfate) were mapped using ArcMap. In addition, Thiessen maps were created around rig/frack water supply wells to estimate the timing and volumes of water extracted from each water supply well to supply HF events within the catchment area of the well. Total water volumes pumped to supply HF events from specific aquifers were then included in a MODFLOW model of the aquifer to assess how the pumping impacted water levels in the aquifer over time (2009-2019). Our review of the analysis suggests that the water quality in the study area varies significantly, ranging from fresh to saline and TDS varies from 100 to 4000 mg/L in these aquifers. This project will help with water management of the aquifers beneath University Lands property which have been the site of HF activity for over 10 years. The maps and models describing the impacts from pumping under several possible future scenarios on water level changes will guide operating companies working on the University Lands acreage to make the most cost-effective decisions on where to get water from, and how that will impact existing aquifer users from other sectors.