Geofluids inferences using deep electrical resistivity tomography for a sustainable energy transition

Abstract

In the last years, the use of Deep Electrical Resistivity Tomography (DERT) has become more common for the investigation of areas with complex geological setting. The considerable resolution obtained through such a technique makes it possible to discriminate much more effectively the resistivity contrasts existing in the shallower crustal levels, thus providing more reliable information on the physical conditions of the rocks, the presence of structural discontinuity surfaces, on the presence and trend in the subsoil of aquifers and/or fluids of various origins.For these reasons, some DERT investigations were carried out in a structurally complex area located close to Tramutola village, in the western side of the Agri Valley, where the largest onshore hydrocarbon reservoir in west Europe is present.The Tramutola site represented a key sector for the early petroleum exploration and exploitation of the area. Natural oil spills were historically known since the 19th century in the investigated area, and these helped the national oil company to identify the first shallower hydrocarbon traces. Furthermore, a considerable amount of sulphureous hypothermal water (~28 °C with a flow rate of 10 l/s) with associated gases (mainly CH4 and CO2) was found during the drilling of the “Tramutola2” well (404.4 m) in 1936. From a geological point of view, the study area, is characterized by the presence of a complete section of the tectonic units of the southern Apennines and a complex structural framework, not yet fully clarified, which affect fluids circulation.To foster the efficient and sustainable use of the geothermal resource in Tramutola area, surface and subsurface geological, hydrogeological and new geophysical data were combined in order deepen our knowledges about the reservoir of the hypothermal fluids and their circulation.The municipality of Tramutola is interested in the rehabilitation of the abandoned oil wells, both in terms of exploitation of the geothermal resource and for the realisation of a tourist “Park of energy”. The aim is to provide a wide audience with strategies, models, and technical skills capable of making visitors more active and critical towards the sustainable use of energy resources. Furthermore, the possible exploitation of geothermal resources of the Tramutola site represents a strategic action in the Basilicata region as a prototype of energy transition from fossil fuels to more environmentally friendly energy resources. This is also essential to satisfy the increased demand for clean energy in the area (no. 7 affordable and clean energy United Nations’ SDGs) and also contribute to climate change mitigation through the reduction of CO2 emissions (13 climate action).