GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 3.1 593 GEOTHERMAL ANOMALIES IN A SECTOR OF THE EASTERN PO PLAIN D. Rapti 1 , A. Grande 2 , R. Caputo 2 , F.C. Molinari 3 , G. Torri 3 1 New Energies And environment, spinoff company, University of Ferrara, Italy 2 Department of Physics and Earth Science, University of Ferrara, Italy 3 Servizio Geologico, Sismico e dei Suoli, Regione Emilia Romagna, Bologna, Italy The European and National strategies for the climate and the energy have as major targets the decarbonisation process before 2050 and the drastic reduction of the PM10 concentration in the Po Plain. In order to achieve these goals, the request, the exploitation, the use and the diffusion of renewable energies should greatly increase in the next future. Due to the recent evolution of technological plants, like district heating, the low-to-medium enthalpy geothermal plants perfectly fulfil the above needs with important environmental, economic, societal, and health benefits. The present research is motivated to contribute to the above needs and particularly to the characterization of the geothermal reservoirs existing in the broader Ferrara-Modena territory, Northern Italy, which hosts in the subsoil some major tectonic structures with a high geothermal potential, like the Ferrara anticline (Fig. 1). The research was based on the analysis of 55 boreholes drilled in the past all over the investigated area for hydrocarbon explorations and available from theVIDEPI database (web site of the Ufficio Nazionale Minerario per gli Idrocarburi e le Georisorse ). The temperature data of these wells have been published in the inventory of the national geothermal resources edited by Agip (1977-1987). It is noteworthy that the available values of the measured temperatures were affected by the fluids (water andmud) used during the drilling operations. The difference between the temperature of the mud and that of the rock depends on several factors like the borehole depth, the time required by the muds for a complete circulation cycle, the thermal gradient, the porosity of the stratigraphic units, the time lag of the measurement. In order to discriminate the influence of the circulation fluids and estimate the real temperature of the surrounding rocks, we Fig. 1 - The 55 boreholes (yellow circles) analysed in the present research. Base map from Bigi et al. (1990).