History match simulation of Serrazzano geothermal reservoir

The simulator SHAFT79 of Lawrence Berkeley Laboratory has been applied to field-wide distributed parameter simulation of the vapor-dominated geothermal reservoir at Serrazzano, Italy. Using a three-dimensional geologically accurate mesh and detailed flow rate data from 19 producing wells, a period of 15.5 years (from 1959 to 1975) has been simulated. The reservoir model used is based on field measurements of temperatures and pressures, laboratory data for core samples, and available geological and hydrological information. The main parameters determined (adjusted) during development of the simulation are permeabilities and much of the initial conditions. Simulated patterns of pressure decline show semi-quantitative agreement with field observations. The simulation suggests that there is cold water recharge and/or incomplete heat transfer from he rock due to fractures in the margins of the reservoir, and some steam flowing to the main well field originates from deep fractures rather than from boiling in the two-phase zones modeled. Simulation methodology and ambiguity of parameter determination is discussed