WATER-USE REQUIREMENTS ASSOCIATED WITH HYDRAULIC FRACTURING WITHIN THE WILLISTON BASIN

Over the last decade, the rapid development of energy resources in the Upper Missouri River Basin, specifically in the Williston Basin, and the corresponding water resources needed to support energy development, has raised concerns of aquifer mining and water-level declines. Of particular concern is the amount of fresh water required to extract the oil and gas using hydraulic fracturing methods—in some cases, about three million gallons is needed to develop each well. Water is withdrawn from local aquifers and/or surface waters and then piped or trucked to the well pad. The withdrawal rate at many of these water sources can often exceed the sustainable recharge rate under current climatic conditions. The water that is returned to the surface after the fracturing process is often disposed in deep formations and effectively removed from the water cycle.

To date, there has been limited analysis of the amount of water used for hydraulic fracturing. Data that identify the factors (technological, geological, and geographic) that influence the amount of water used for hydraulic fracturing at each oil and gas site is particularly lacking in analysis. Additionally, little is known about the partitioning of disposal methods, including recycling. This lack of information prohibits fact-based management of the groundwater and surface water resources.

The objectives of this ongoing investigation are to (1) obtain and analyze water-use data at a well site (process) level, (2) identify the primary factors (predictor variables) controlling water use, and (3) identify the predictor variables controlling water recycling and disposal. Using available and surveyed water-use and disposal data, mathematical relations are being developed between the predictor variables and water-use and disposal quantities. These relations will then be used to estimate water-use requirements in the Williston Basin with respect to ongoing and future hydraulic fracturing and provide data for concurrent groundwater modeling studies to estimate groundwater availability under various development scenarios.