The Colorado Geological Survey, a branch of the state Department of Natural Resources, unveiled Jan. 26 a web tool to help the public visualize geologic conditions in the Niobrara Formation.
The Niobrara is the focus of oil and natural gas development and production through the use of horizontal drilling and hydraulic fracturing.
Citizens around the state have been seeking a better understanding of how ground water supplies are protected amid energy development and the geologic conditions that separate ground water from the oil and natural gas deposits in the Niobrara.
The purpose of the tool is to answer the following questions: If a company were to hydraulically fracture the Niobrara formation under a house, how deep would this be occurring? How thick would the shale barrier be between the house’s water well and the Niobrara strata?
“The tool is designed to help people visualize the spatial relation of hydraulic fracturing in the Niobrara Formation to important fresh-water aquifers,” according to a CGS news release. “The tool will show the average depth to the Niobrara Formation at any selected point on the map.
“It will also show the minimum thickness of the shale barrier (Pierre Shale) that separates the Niobrara strata from fresh-water aquifers and the depth of the deepest fresh-water aquifer at any spot on the map.”
According to the CGS website, the Pierre Shale is a stack of rocks that ranges in thickness from a half a mile to more than a mile and a half thick.
It has a low level of permeability making it an ideal barrier between ground water supplies close to the surface and the Niobrara formation, which in some locations can be thousands of feet below sea level, according to the calculation tool.
Currently, the CGS has mapped the Niobrara, the Pierre Shale and fresh-water aquifers in the Denver Basin.
CGS is in the process of collecting data to expand the tool to other parts of the state.
To view the online map, visit geosurvey.state.co.us/energy/Oil/Pages/NiobraraCalculationTool.aspx.
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