Revision, calibration, and application of the volume method to evaluate the geothermal potential of some recent volcanic areas of Latium, Italy

Evaluation of the Theoretical Geothermal Potential of Inferred Geothermal Reservoirs within the Vicano–Cimino and the Sabatini Volcanic Districts (Central Italy) by the Application of the Volume Method

“…Table 2. Evaluation of fluid production rate (t/h) and theoretical geothermal potential (MWt) [13,20] calculated through the revised volume method of [14] for the VCVD and the SVD. A = area of the geothermal reservoir calculated by kriging; h = average thickness of the geothermal reservoir; V = volume of the geothermal reservoir; Q = discharge rate of the geothermal fluid; T min-max = minimum and maximum temperatures of the geothermal reservoir; W = theoretical thermal power.…”

“…The theoretical geothermal potential (W) of the identified geothermal reservoirs (Table 2), which is comparable to the thermal energy in [42], has been computed according to the equation [14] …”

“…The hourly production rate (Q) of the potential geothermal systems has been computed multiplying the volume of each geothermal reservoir for its specific productivity. The average specific productivity of 40 t/h km 3 , calculated for the liquid-dominated geothermal systems of Latium by [14] has been used for calculations. Reservoir temperatures have been derived taking into account, hierarchically, data from: (1) deep drilling (i.e., bottom-hole temperatures); (2) geothermometric evaluations based on chemical equilibria of gas species [19,[39][40][41]; and (3) the map of temperature of the potential reservoir top [12].…”

“…where A is evaluated on the basis of the pCO2 distribution of emerging waters ( Figure 5) and h is calculated from the difference between the depth of the potential reservoir top and the depth of 3 km, which is usually considered the maximum depth for an economically exploitable geothermal resource (Table 2) [11,14]. All available information on: (1) the geological structure at depth and (2) the depth of the potential reservoir top have been acquired from the Ministry of Economic Development website [12].…”

“…In more recent years, the old approach has been reviewed with the introduction of the CO 2 surveyed in the regional aquifers as a tracer for reservoir productivity [14], as typical geothermal systems exhibit an anomalous CO 2 degassing of deep provenance in areas of high heat flux [15][16][17][18][19]. In this paper, a revised version of the volume method has been applied to estimate the theoretical geothermal potential [20] of inferred geothermal reservoirs within the Vicano-Cimino Volcanic District (VCVD) and the Sabatini Volcanic District (SVD) in the Latium region.…”