The geothermal favourability of geopressured-geothermal systems: a case study in Italy

We present an innovative methodology to assess geopressured-geothermal resources occurring in terrigenous units in sedimentary basin plays. This kind of resource is considered unconventional due to economic and technical barriers, but is particularly of interest for the possibility either to improve the economic feasibility of an industrial geothermal project or to deploy the uneconomic/depleted abandoned hydrocarbon wells. This paper is intended to be a practical analytical framework for the systematic integration of the relevant data required to assess these resources. For this purpose, innovative parameters were also implemented in the methodology. The final result is the favourability map for identifying prospective areas to be further investigated for the appraisal of the geopressuredgeothermal potential. We applied our methodology to the foredeep-foreland domains of the Apennines thrust belt (Abruzzo region, central Italy). We analysed hundreds of deep hydrocarbon wells in order to create 3D geological and thermo-fluid dynamic models at a regional scale as well as to obtain information on the pressure regimes and on the chemistry of the system. The final favourability map for the Abruzzo case study is a first attempt at ranking these kinds of unconventional geothermal resources in a region that has been historically explored and exploited mostly for hydrocarbons.