This publication identifies oil and gas wells in Colorado that may be prospective for access to geothermal resources and potentially open for re-entry. Geothermal gradient and heat flow were estimated for all wells contained in the Colorado Oil and Gas Conservation Commission’s (COGCC) oil and gas well shapefile (http://cogcc.state.co.us/) downloaded on June 4, 2009. According to provided locations, each well was assigned geothermal properties (gradient and heat flow) using the interpreted gradient and heat flow zones shown in the CGS publications, MS-51 Interpretive Geothermal Gradient Map of Colorado, and MS-45 Interpretive Geothermal Heat Flow Map of Colorado. Each well was assigned a “tier rank” for its estimated gradient and a tier rank for its estimated heat flow, to identify the wells located in areas of the state with superior geothermal properties. It is important to remember that the oil and gas wells were assigned geothermal property ranges and tier ranks based on interpretive maps of gradient and heat flow, not on intrinsic data from each well.
Tier 1 wells represent the top ~2% of wells for each of the geothermal properties (gradient and heat flow), Tier 2 wells represent the top ~5%, Tier 3 wells represent the top ~15%, and Tier 4 wells represent those that are below the top ~15% of wells for each of the geothermal properties. The gradient and heat flow cutoff values used in creating these tiers are shown in the map legend. Wells were separately assigned to tiers for both estimated gradient and heat flow. As a result, wells can be in a different tier for geothermal gradient than they are for heat flow. Using these tiers, oil and gas wells on this map are divided into two general categories – “Most Prospective Geothermal Wells” and “Additional Prospective Geothermal Wells”. Digital ZIP/GIS/PDF download. MS-48D