Estimation of the geothermal potential in the Loranca sub-basin, NE Alto Guadiana area (Central Spain) based on 3D modelling and petrophysical properties

This study presents a methodology for estimating the geothermal potential of the Loranca sub-basin, located in the north-eastern part of the Alto Guadiana region (Central Spain). The approach integrates rock petrophysical data with a 3D geological modelling. Laboratory analyses of rock samples collected near the study area were conducted to characterise key petrophysical properties, including thermal conductivity, thermal diffusivity, specific heat capacity, and density. These petrophysical parameters, combined with the regional boundary conditions, were incorporated into a 3D geological model of the area using Geomodeller software to simulate temperature distribution with depth. The geological and thermal models were exported and processed with the 3DHIPCalculator software to evaluate deep geothermal potential. 3DHIPCalculator code, through a probabilistic Monte Carlo approach, provided estimates of the Heat in Place (HIP) and Recoverable Heat (Hrec) for the aquifer. These models illustrate depth-temperature relationships and highlight the Jurassic aquifer as the most promising lithology for heat storage. The results reveal a low geothermal potential for the Jurassic unit, suitable mainly for low-enthalpy geothermal applications (heating and cooling systems, balneotherapy, greenhouses, etc. ). This methodology reduces uncertainty in resource estimation and provides a reproducible tool for future geothermal assessments. KEYWORDS: Geothermal, Petrophysics, 3D Thermal Modeling, Heat in Place, Recoverable Heat.