Assessing thermal regime variability in the San Francisco Basin (Argentina): Heat flow and geothermal gradient anomalies derived from hydrocarbon exploration well data

The Santa Bárbara (SB) mountain range (Andean foreland, northern Argentina) has become increasingly significant in recent years for geothermal exploration, due to the presence of several hot and mineral springs with outlet temperatures of up to 40–60 °C. In this study, bottom-hole temperatures (BHT) from 24 oil wells located within the San Francisco Basin (north of Santa Barbara) were utilized to assess the thermal flow and to investigate the origin of the thermal anomalies. The BHT values, ranging from 44.4 °C to 220.2 °C, indicate a geothermal gradient ranging from 24.9 to 40 °C, a heat flow between 97 and 153 mW/m², and a thermal conductivity of 3.49–4.27 W/mK for the main reservoir unit (Yacoraite Formation). The derived geothermal and geological units, in conjunction with 2D seismic lines and topographic data, were utilized to map relevant structural variations, changes in thickness, and major lithological units. The conceptual model identified the northeastern and southwestern regions as two areas of equal potential for medium- to high-temperature fluid resources. The calculated 'heat-in-place' (HIP) values confirm the substantial geothermal potential of the Yacoraite Formation within the San Francisco Basin by indicating the presence of significant stored thermal energy. The findings of this study demonstrate that integrating well logging and space data with geospatial techniques is an effective method for geothermal prospecting in geological and tectonic settings within foreland environments.