A new web-based tool developed by the Colorado Geological Survey allows the public to better understand and visualize geologic conditions that separate groundwater supplies from the oil- and natural gas-bearing Niobrara Formation in the Denver Basin. The web tool can be found at geosurvey.state.co.us/energy/Oil/Pages/NiobraraCalculationTool.aspx
The Niobrara is the focus of exploration and development for oil production using horizontal drilling and hydraulic fracturing. The development is occurring in parts of the Denver Basin where many people depend on groundwater. Some citizens are seeking a better understanding of how water supplies are protected amid energy development.
The tool is designed to help people visualize the spatial relation of hydraulic fracturing in the Niobrara Formation to important fresh-water aquifers. The tool will show the average depth to the Niobrara Formation at any selected point or address 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. The tool also provides the depth of the deepest fresh water aquifer at any spot on the map.
The tool can help answer questions such as: If a company were to hydraulically fracture the Niobrara formation underneath my house, how deep would this activity occur? How thick would the shale barrier be between the aquifer where my well draws water and the Niobrara strata? The web tool homepage also provides important geologic diagrams and explanatory text to provide further detail about the geologic conditions in the Denver Basin.
The tool allows a person to locate an area of interest by clicking on a map of the Denver Basin and zooming into their neighborhood. A user can also type in an address, including the city, state and zip code, to receive information. The resulting data includes estimated depths to the top of the Niobrara Formation, the estimated depth to the base of the Fox Hill Sandstone (the deepest of the administrated Denver Basin aquifers) and the total thickness of the Pierre Shale, the rock layers between the Niobrara and the Fox Hills.