Possibilities for CCUS in medium temperature geothermal reservoir

Abstract Based on the hypothetical structure, a 3D numerical simulation model was created to examine the flow characteristics of a geothermal field. According to the known dimensions, assumption of existing fault and petrophysical properties, the model can relate to the properties of Velika Ciglena geothermal reservoir, and thus the simulation results of heat flow (reservoir cooling due to reinjection of cooled water), wellbore injectivity and productivity are comparable with previously published data related to the same field. This simulation model for a geothermal reservoir of such structure has been made for the first time and was complemented by an analysis of possible CO2 injection. It has been established that the effect of CO2 storage is significant until CO2 reaches the production well (first two years). The effect of pressure relief on the CO2 injection well has been achieved because of simultaneous injection and production and due to an increase in CO2 saturation which had consequently induced an increase of the effective permeability for CO2. The effect of reservoir cooling is shown, which is significant only when the water is injected, while in the case of injection and production of CO2, this effect does not reflect on the temperature of the produced fluid.