Oil and gas development in the Williston Basin often involves the extraction of saline brines and presents a major source of saline contamination to surface and groundwater resources. The Prairie Pothole Region (PPR) is superimposed over much of the Williston Basin and provides critical habitats for migratory birds and waterfowl. Surface and shallow groundwaters in the PPR often contain high levels of total dissolved solids (TDS); however, salts produced from energy development are chemically different than the near-surface salts. To differentiate between saline contaminated and naturally high TDS water samples, Reiten and Tischmak (1993) developed a Contamination Index (CI = chloride concentration / specific conductance),...
U.S. Geological Survey scientists and cooperating partners are examining the potential risk to aquatic resources (for example, wetlands, streams) by contamination from saline waters (brine) produced by petroleum development in the Williston Basin of Montana, North Dakota, and South Dakota. The primary goals of this study are to provide a science-based approach to assess potential risk of brine contamination to aquatic systems and to help focus limited monitoring and mitigation resources on the areas of greatest need. These goals will be accomplished through field investigations that quantify brine movement and risk assessments using remotely-sensed and other spatial datasets.
Groundwater, surface water, and soil in the Goose Lake oil field in northeastern Montana have been affected by Cl-rich oil-field brines during long-term petroleum production. Ongoing multidisciplinary geochemical and geophysical studies have identified the degree and local extent of interaction between brine and groundwater. Fourteen samples representing groundwater, surface water, and brine were collected for Sr isotope analyses to evaluate the usefulness of 87Sr/86Sr in detecting small amounts of brine. Differences in Sr concentrations and 87Sr/86Sr are optimal at this site for the experiment. Strontium concentrations range from 0.13 to 36.9 mg/L, and corresponding 87Sr/86Sr values range from 0.71097 to 0.70828....
The Williston Basin, in north-central United States and south-central Canada, has been a leading source of domestic oil and gas production for more than 50 years. This region, which includes parts of Montana, North Dakota, South Dakota, Saskatchewan, and Manitoba, is currently in the midst of a modern energy boom driven by advances in oil and gas production technologies. The main energy-producing formations associated with the current boom are the Bakken and Three Forks. A portion of the Williston Basin is overlain by the Prairie Pothole Region (PPR), which is known for its depressional wetlands that provide critical breeding and nesting habitats for a majority of North America’s migratory waterfowl as well as habitat...
Water (brine) co-producedwith oil in the Williston Basin is someof themost saline in the nation. The Prairie Pothole Region (PPR), characterized by glacial sediments and numerous wetlands, covers the northern and eastern portion of the Williston Basin. Sheridan County, Montana, lies within the PPR and has a documented history of brine contamination. Surface water and shallow groundwater in the PPR are saline and sulfate dominated while the deeper brines are much more saline and chloride dominated. A Contamination Index (CI), defined as the ratio of chloride concentration to specific conductance in a water sample, was developed by the Montana Bureau of Mines and Geology to delineate the magnitude of brine contamination...
Brine contamination of groundwater in the East Poplar oil field was first documented in the mid-1980s by the U.S. Geological Survey by using hydrochemistry, with an emphasis on chloride (Cl) and total dissolved solids concentrations. Supply wells for the City of Poplar are located downgradient from the oil field, are completed in the same shallow aquifers that are documented as contaminated, and therefore are potentially at risk of being contaminated. In cooperation with the Office of Environmental Protection of the Fort Peck Tribes, groundwater samples were collected in 2009 and 2010 from supply wells, monitor wells, and the Poplar River for analyses of major and trace elements, including strontium (Sr) concentrations...
