Retrospective Case Study in Killdeer, North Dakota, Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources.
Citation:
Beak, D., G. Oberley, S. Acree, C. Ruybal, AND R. Ross. Retrospective Case Study in Killdeer, North Dakota, Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/103, 2015.
Impact/Purpose:
As a component of the EPA’s National Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources (US EPA, 2012), five retrospective case studies were conducted to investigate reported instances of drinking water resource contamination in areas of natural gas development and use of hydraulic fracturing technology. These studies were intended to inform primary research questions related to the hydraulic fracturing water cycle (US EPA, 2012).
Description:
This report describes the retrospective case study conducted near Killdeer, Dunn County, North Dakota. The Killdeer study area is the location of historical oil and gas production, with current unconventional oil and gas production occurring in the late Devonian/early Mississippian-aged Bakken Shale. In September 2010, a known blowout occurred at this site during the hydraulic fracturing process to complete the well. This resulted in a release of hydraulic fracturing fluids, oil, and flowback water onto the land surface and possibly into the Killdeer aquifer. After the blowout, the state initiated remediation efforts. Water quality samples were collected from domestic, monitoring, supply, municipal, and state wells during three rounds in July 2011, October 2011, and October 2012. The geochemistry of water samples was investigated by analyzing major ions, trace metals, methane/ethane gas concentrations, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), glycol ethers, diesel- and gasoline-range organics (DRO and GRO), low-molecular-weight acids, and selected stable isotopes (δ18OH2O, δ2HH2O, and 87Sr/86Sr). Major ion data collected from this study were compared with historical water quality data retrieved from the literature and national water quality databases. These data sources provided water quality data for samples collected prior to major development of the Bakken Shale play and provided an initial screening for potential ground water contamination. Statistical comparisons were made between the data collected from this study and the historical data. In order to help determine whether hydraulic fracturing or processes related to hydraulic fracturing were the cause or one of the causes of alleged impacts on water quality, other potential contaminant sources were identified by conducting detailed environmental record searches.The study identified two impacted monitoring wells that had water quality different from the other study wells and historical data. The main impact on water quality in these two wells was from briny water and TBA mixing with Killdeer aquifer water. Based on the data analysis performed for the Killdeer case study, the observed impacts to the two wells are consistent with the blowout that occurred on the Killdeer pad.
URLs/Downloads:
https://www.epa.gov/hfstudy/report-retrospective-case-study-killdeer-north-dakota-pdfRetrospective Case Study in Kildeer, North Dakota
Fact Sheet: Kildeer, North Dakota Retrospective Case Study