Oil and Gas Evaluation
In eastern Montana, the Bakken Formation is an important source of oil and natural gas. Horizontal drilling and hydraulic fracturing play a critical role in the successful production of Montana's largest oil reservoir. The MBMG provides hydrogeologic and geologic information to individuals, public agencies, and the petroleum industry.
Groundwater sampling near oil and gas production
To address requests from citizens concerned with increased development and new development practices, the MBMG collaborated with the Montana Department of Natural Resources and Conservation (DNRC) and the Montana Department of Environmental Quality (DEQ) to characterize groundwater quality near current oil and gas development. Analyses included a wide range of organic constituents, isotopes of carbon and hydrogen of methane, and the standard inorganic constituent analysis.
Groundwater level drawdown
Recently collected data show substantial water-level declines in the Fox Hills–Hell Creek aquifer. In some cases this decline has left ranchers without stock water. Possible causes are being evaluated through a computer-generated groundwater model. The modeling effort will be used to replicate the current conditions and simulate the aquifer’s response to predicted increases in water use.
Water resources in eastern Sheridan County
The MBMG has worked with the U.S. Geological Survey and the U.S. Fish and Wildlife Service documenting impacts of oil development on water resources. The work has documented contamination from water co-produced with hydrocarbons. A Contamination Index (CI) developed by the MBMG over 20 years ago uses field values to determine the ratio of chloride to specific conductance. CI ratios greater than 0.035 typically indicate contamination from water co-produced with hydrocarbons. Recently completed projects have documented wetlands, lakes, and groundwater contaminated by oilfield wastes.
For more information on regulations contact the
Montana Board of Oil and Gas Conservation.