Geothermal Play Fairway Analysis (GPFA): A Texas/Gulf Coast Case Study

Abstract Geothermal Play Fairway Analysis (GPFA) is an exploration process adopted to geothermal, that integrates data of critical risk elements inherent to that specific geothermal play type. The key function of GPFA is to reduce risk and increase focus for improving exploration success rates. GPFA begins at the regional/basin scale, and progressively focuses in on the play scale. It then examines the critical risk element data to highlight which play areas have the highest likelihood of success (prospects). The outputs from the GPFA process are Common Risk Segment (CRS) & Composite Common Risk Segment (CCRS) Maps. CRS maps define areas that contain the same general Probability of Success (PoS) for each individual risk element based on the input data. Operator analyzed/ determined cutoff values or classes are then applied to each map with color assignments indicating high (red), medium (yellow) and low (green) risk areas for each element under consideration. Each individual CRS map is then composited into a single CCRS map. Publicly available data on hundreds of thousands of boreholes in Texas and the Gulf Coast demonstrate excellent potential for geothermal electricity generation from either current or abandoned oil and gas wells. Near-surface geothermal resources, at depths of 3 km (9,842 ft) or less, are generally less than 150°C (302°F) in Texas. Economically feasible electricity generation is possible with available subsurface temperature conditions within reasonable depths—generally greater than 120°C (248°F) within 4 km (13,123 ft) – given the prolific oil and gas well drilling. Extensive data exists to depths as much as 8 km (26,246 ft), indicating temperatures in excess of 300°C (572°F).