Geothermal 3D model of the shallow crustal structure in the Val d’Agri oil field (Basilicata region)

Abstract

A good understanding of the geothermal gradient in any region is of primary importance for hydrocarbon/geothermal reservoir management and further applications in the fields of (e.g.) subsurface CO2 storage and nuclear waste disposal. In the particular case of the Basilicata oil fields area, the analytical definition of the geotherms carried out in this study is particularly relevant, both for industrial applications and for seismotectonic modelling in a region characterized by a magnitude 7 historical earthquake. In fact, the thermal state plays a fundamental role in controlling the modes of strain accommodation in the crust, which in turn controls the partitioning and distribution of seismic vs. aseismic strain. A geothermal model for the area of the Val d’Agri oil fields has been obtained by an analytical procedure. The model takes into account both the temperature variation due to the re-equilibrated conductive state after thrusting and frictional heating. Input parameters include heat flow density data and a series of geologically derived constraints – thrust depth, timing of thrusting, slip rate – obtained by the integration of surface and subsurface datasets. This work, representing a first attempt to reconstruct a geothermal 3D model for the Val d’Agri seismic zone of the Basilicata region, provides thermal constraints that could constitute a basis for future studies in the area.