--> --> Abstract: New Horizons for Geothermal Energy in Sedimentary Basins in Colorado, by Paul Morgan and Matthew A. Sares; #90124 (2011)

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Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

New Horizons for Geothermal Energy in Sedimentary Basins in Colorado

Paul Morgan1; Matthew A. Sares1

(1) Coloroado Geological Survey, Denver, CO.

During the past decade, projects in Europe have demonstrated the feasibility of generating electricity from relatively low-temperature geothermal resources in sedimentary basins, including in conjunction with direct use projects. Major sedimentary basins in Colorado include the Denver Basin, the Piceance Basin, the San Luis Basin, the northern half of the Raton basin, and portions of the Paradox and San Juan Basins. All have significant hydrocarbon production, with the exception of the San Luis Basin. Most of the hydrocarbon production is natural gas. With the exception of coalbed methane wells, co-produced water volumes are relatively low. Co-produced water with coalbed methane originates at relatively shallow depths (<1000 m; 3280 ft.) at temperatures too low for electricity generation (<55°C; <130°F). For these reasons, the use of oil and gas co- produced water for geothermal electricity production is limited in Colorado. However, the European model could be adapted for use of sedimentary basin hydrogeothermal resources in Colorado. Where permeability is too low, fracturing technology can be used to increase flow rates for economic power generation.

Bottom-hole temperature (BHT) data are abundant in Colorado, but must be corrected for the cooling effect of drilling fluid circulation. Traditional methods of calculating equilibrium temperatures are not possible with available data. However, many BHTs from cement bond logs are recorded days to weeks after the cessation of drilling in some Colorado wells. These data have provided a useful estimate of equilibrium temperatures from which drilling disturbance corrections have been calculated for the Denver, Raton, and Piceance Basins. BHT data are being systematically re-corrected for the sedimentary basins of Colorado. Based on improved subsurface temperature models, we will investigate the feasibility of producing electricity from well doublets, either through natural aquifers or through enhanced permeability (EGS). The goal is to demonstrate that sedimentary basins have the potential to provide distributed geothermal power to much of the mid-continental US.