| Abstract |
Tularosa Basin is located in the southern Rio Grande Rift. This extension basin reaches from El Paso, Texas, on its southern boundary, northwardly for about 270 km. It is a sparsely populated region within the Chihuahuan Desert that is home to several military installations, including Fort Bliss, White Sands Missile Range, and Holloman Air Force Base, which cover approximately one half of the land area and which would benefit from geothermal energy development. In 2013, the presence of developable geothermal energy was confirmed through a DOE funded drilling project at McGregor Range at Fort Bliss, Otero County, New Mexico. This, in part, provided impetus for a new DOE funded geothermal play fairway analysis project covering the entire basin. Play fairway analysis (PFA) is a term derived from the petroleum industry, where datasets related to charge, reservoir, and seal are integrated into composite risk segment (CRS) layers, which are in turn integrated into a final deterministic PFA model which represents the areas within a basin most likely to contain reservoirs, thus reducing risk. Or project replaced charge, reservoir, and seal with heat, fault related permeability, and ground water for CRS development for geothermal exploration. Quantitative geothermal exploration models have also been developed in the past, but their use has been limited. One such model is created through the application of the weights of evidence (WoE) method, which considers the correlation of evidence layer values with those of training sites located at known geothermal systems and hot springs. This method was also tested and compared with the deterministic petroleum industry PFA method. Supporting data for both PFA analyses consisted of heat flow, temperature gradients, and quartz geothermometers (heat CRS), Quaternary faults and zones of critical stress (fault related permeability CRS), and wells that penetrate ground water and springs (ground water CRS). For the petroleum industry logic PFA, these data were integrated into a final GIS vector based model which identified eight plays. WoE used raster input data and produced a probabilistic raster output, which identified ten plays. Of the 12 total identified plays, six were identified by both methods, two were unique to the deterministic method, and four were unique to the WoE method. Both deterministic and probabilistic certainty maps were also produced to help prioritize plays. The highest priority play was McGregor Range, which was identified by both methods. A medium-high priority play was gleaned from the WoE identified plays and a medium priority play from those produced by the deterministic method. Economic analysis was applied to the three highest priority plays. Both methods allowed the delineation of geothermal plays. However, most were low certainty, which was primarily due to data paucity. WoE identified the greatest number of plays; however, it is unknown if its apparent greater sensitivity is real. Play veracity will require additional work. Of the medium to high priority plays, economic analysis indicates that development could take place with reasonably low risk. |