GEOTHERMAL RESOURCE SCREENING IN THE DENVER-JULESBURG BASIN USING 3D BASIN MODELING

A 3D basin model was developed to aid in the evaluation of geothermal resource potential in the Denver-Julesburg Basin of Colorado and Wyoming. The model was constructed using legacy datasets from oil and gas development in the basin integrated with recently updated paleoenvironmental maps to assign lithologies on a basin-wide scale. The integration of lithological interpretations from paleoenvironmental maps facilitated the assignment of lithology-specific thermal properties. The model was made up of 3D grid with ~800,000 cells. Tops for 24 depositional units were defined and lithologic properties were assigned to each cell. Bottom-hole temperature (BHT) measurements (~20,000) used in the model were corrected using a Förster-type model developed for the Denver-Julesburg Basin. The corrected temperatures ranged from ~55°C to 225°C. Wells within equal-area cells were grouped to create depth-temperature profiles for heat flow calibration. The model simulations with heat flow values between 50 and 80 mW-m² were run and the value that best matched the corrected temperature profile in each cell was selected and contoured into a heat flow map. Aeromagnetic data was also used to delineate basement features in areas with limited well data. Once calibrated using temperature data to estimate heat flow, formation specific and depth to temperature maps showing the distribution of geothermal potential in the basin were extracted. Calibrated model results derived indicate highly elevated heat flow in the Wattenberg field area. Depth to temperature maps generated for moderate- (≥90°C) and high-temperature (≥150°C) geothermal resource suggest that, in some areas, moderate and high-temperature resources may be as shallow as ~1,200 and 2,130 meters, respectively. Deeper geothermal resource potential was also indicated in other areas. This basin-wide model of the Denver-Julesburg Basin identifies general geographic areas and depth intervals where potential geothermal resources may be located and could be developed for a wide range of thermal energy applications, depending on permeability. Low permeability units with favorable depth-temperature combinations could be targets for closed-loop technologies or installation of engineered geothermal systems.