3D GEOLOGICAL MODELLING AND GEOTHERMAL ASSESSMENT OF THE LIMAGNE BASIN (FRANCE) Z-99

Summary This work consists in assessing the geothermal potential of the Limagne area (Massif Central, France) in 3D by building a geological model and computing a thermal model. This reservoir is a Tertiary graben belonging to West European rift system characterized by a geothermal anomaly with Tertiary clastic reservoirs. In order to better understand the geometry of geology, various geological and geophysical data acquired during various campaigns are re- interpreted to construct a coherent 3D model. The new interpretation consists in a 35km x 30km x 5km geological model extending from the basement to the surface of the basin. The geometry is then used to constrain a numerical model (assuming a diffusive temperature regime) based on the thermal conductivity of the various geological units and thermal boundary conditions. The total amount of geothermal energy available for each aquifer is computed, and the geothermal potential i.e. the recoverable energy, is mapped over the entire model.