THERMAL ENERGY IN PLACE IN TEXAS: A NOVEL METHOD FOR ESTIMATING ACCESIBLE GEOTHERMAL POWER WITH EXISTING OIL AND GAS WELLS USING ARCGIS

Texas’ large sedimentary basins in the Gulf Coast, East Texas, Anadarko Basin, and West Texas are ideal for transitioning from hydrocarbon to geothermal power production because of the existing infrastructure associated with oil and gas operations. This effectively lowers start-up costs for geothermal power production schemes and provides an opportunity for oil and gas companies to maintain usage of otherwise depleted wells.

The Gulf Coast and Anadarko Basin have previously been analyzed for thermal energy in place, though formations in East and West Texas have not (Papadopolus, 1975; Esposito and Augustine 2012). These studies over-estimate thermal energy by employing the Muffler (1979) method in which the basin is split into one or more temperature-blocks for which the thermal energy in place in calculated. In the present study, ArcGIS is utilized to create a maximum depth raster for existing wells in regions of Texas. The geothermal gradient raster for the region is then integrated over the block volume to create thermal energy in place estimates. Extractable energy is then derived from the energy in place using the existing heat rate, or efficiency of existing binary cycle generators in their conversation of thermal energy to electrical energy.

Preliminary results indicate 9.42E+21 Joules (1.88E+12 MWhrs extractable) for the Gulf Coast, 8.34E+21 Joules (1.65E+12 MWhrs extractable) for the East Texas, 8.66E+21 Joules (1.71519E+12 MWhrs extractable) for the West Texas, and 3.85E+21 Joules (7.63047E+11 MWhrs extractable) for North Texas. In order to put these numbers in perspective, the latest estimates of the proven reserves of crude oil and natural gas in Texas by the US DOE Energy Information Agency (Annual Energy Outlook, 2012) combined are 1.3 E+17 Joules.