3D Structural modeling for geothermal potential evaluation in Southern Apennines

Deep geothermal systems as a renewable and green source for energy production and for heating and cooling activities has a great potential for development in many European countries. Also, the need to expand the use of the geothermal resources is well supported by the Foundation for Sustainable Development and meets the goals of the UN 2030 Agenda. Under this perspective, the aim of this research is to study the geothermal energy as an under-exploited tool and how this natural resource could improve and support the ecological transition. The area of interest focuses on the subsurface Cretaceous-Eocene fractured shallow water carbonates (Apulia platform) in the Campania-Lucania sector of the Southern Apennines (Italy), where, based on previous studies, a geothermal positive anomaly has been detected at the level of the reservoir approximately at -3000m (below ground level). The presence of this heat anomaly and in particular the heat transfer mechanism (fluid migration, thermal conductivity, fractures) have not been satisfactorily yet explained from a structural point of view which seems to be one of the key factors for this anomaly. A wide public and confidential database including reflection seismic profiles, well data, gravimetric information and literature from the academia and the Oil and Gas Industry discussing the different structural styles, allowed the re-interpretation and the 3D reconstruction of the geological structures which is subsequently internally characterized by investigating the faults and fractures where hot fluids are present and circulate in the deep subsurface. The structural setting, the physical characteristics of the reservoir rock, the chemical-physical properties of the fluids in the deep subsurface and the dispersion of the heat potential of these fluids as they rise to the surface are all elements that must be considered in the screening phase of potential areas for the development of this geothermal project. We present a comprehensive synthesis of the available data which elaborates the temperature/heat observations derived by the subsurface data and explains sufficiently enough the heat anomaly observed in the area. The geological model is the foundation break of this research and the first fundamental input for the geomechanical characterization of the rock mass by defining the main fracturing trends and the large-scale fractures (discrete fracture network) as the main potential conduits and paths for hot fluid migration and circulation.