Numerical Modeling of Potential CO 2 -Fed Enhanced Geothermal System (CO 2 -EGS) in the Gorzów Block, Poland

This article presents the results of numerical modeling for a hypothetical CO 2 -EGS system in the volcanic rocks of the Gorzów Block, Poland. Modeling was carried out in the following stages: in phase 0, modeling of the fracturing process was performed, as a result of which the permeability distribution for the newly created fractured zone was obtained. Next, the process of saturating the EGS reservoir with CO 2 was modeled until pure CO 2 could enter the production well (phase 1). Then, a multi-variant simulation of heat production was performed (phase 2). The obtained results allowed for drawing interesting conclusions: (1) the duration of phase 1 may take several years unless a sufficiently high injection rate of CO 2 is supplied, (2) the higher the injection rate of CO 2 , the lower the cumulative storage ratio of CO 2 , and (3) most of the CO 2 storage in the formation takes place in phase 1, while even 92% of the CO 2 injected in phase 2 can be recovered via the production well. Despite the environmental benefits connected with structural trapping of CO 2 , the Gorzów Block has probably too low formation temperature (145 °C) and too low stimulated volume (~0.1 km 3 ) to deliver satisfactory and stable thermal output.