Given the "boom" label placed on Bakken/Three Forks shale formation oil/natural gas production, the U.S. Geological Survey (USGS) has directed scientists to undertake multiple studies of water quality in the parts of the sprawling Williston Basin found in North Dakota.
“The multiple ongoing USGS studies in the Williston have various completion dates,” USGS investigator Joanna Thamke told NGI’s Shale Daily on Tuesday. “The groundwater availability study is projected to conclude in 2016.”
USGS officials want to determine if water quality has been, or could be, affected in shallow glacial and bedrock aquifers from the use of hydraulic fracturing (fracking) or deep well injection activities. They worry about possible contamination from fracking chemicals or from the heavily saline produced water coming from petroleum-bearing rock formations.
Thamke said USGS is coordinating with several state, tribal, federal and Canadian provincial agencies.
USGS recently published a report on the uppermost principal aquifer systems in the Williston and Powder River basins on both sides of the U.S.-Canada border. The report's framework and conceptual model are critical to understanding the flow directions within and between the shallow aquifers.
Citing the Williston's "modern energy boom" because of the Bakken/Three Forks formations, the USGS said "these technologies have allowed access to previously untapped energy resources, but at the price of using large quantities of the limited surface water and shallow groundwater resources."
In addition to the increased use of freshwater supplies for fracking processes, a recent USGS study of the Williston and Powder River areas cited additional development of "coal, lignite, and coalbed natural gas resources" in both basins as potentially affecting "the shallow aquifers by strip mining and groundwater depletion."
USGS characterizes the Williston Basin region as semi-arid, with annual total precipitation ranging 11-21 inches, west to east in the basin. Thus, the main source of groundwater recharge in the basin is precipitation, which it says is less than a half-inch annually for recharge purposes in most areas.
USGS began looking in more depth at the aquifer systems in the basins in 2011, noting the relative shallow (less than 3,000 feet deep) and wide bowl shape of the Williston, and the much deeper, narrower and asymmetrical water system (8,500 feet) in the Powder River area.
In both basins, groundwater flows are generally easterly and northerly.
Using historical and recently acquired investigative data, the USGS developed a hydrogeological framework for the three principal aquifer systems in the two basins. General overviews and studies of the two basins were performed in 1996 and in the 1980s, USGS said.