Hydrogeologic Windows: Detection of Blind and Traditional Geothermal Play Fairways in Southwestern New Mexico Using Conservative Element Concentrations and Advective-Diffusive Solute Transport

摘要

We combine trace element geochemistry and hydrologic tracer transport analysis to identify geothermal upflow zones within southwestern New Mexico. We analyzed about 1400-4000 wells with lithium and boron chemical analyses. Most of the geothermal waters had elevated lithium and boron concentrations (> 0.5 mg/1) that weakly correlate with reservoir temperatures. We used available water-table measurements to construct water-table maps and calculate groundwater flow directions. We used an "upwinding" approach to track mathematical particles through the flow field within the shallow aquifer system. Areas where particles with high tracer concentrations pass wells with low tracer concentrations may indicate the presence of a geothermal upflow zone. The approach was applied to the southern Albuquerque Basin near San Acacia and the southern Engle Basin near Truth or Consequences, NM. Although our approach revealed a potential geothermal upflow zone at Indian Wells spring near San Acacia NM, additional work is needed to refine the methodology. A multiple realization-based methodology for locating tracer sources was also developed. In this method, an advection-diffusion equation was solved for eighty realizations of different source locations in the Socorro-La Jencia Basin area. By comparing simulated tracer concentrations to measured values, a source-likelihood map was drawn, and the tentative source locations were identified. The region of high heat flow within the Socorro-La Jencia Basin at the base of Socorro Peak was found to have a local minimum of the root mean squared error of simulated minus observed normalized lithium concentrations. This suggests that our approach can identify geothermal up flow zones.