Integrated Geological Modeling for Identification of CO2-Enhanced Geothermal System Reservoirs in Poland

Exploitation of geothermal energy stored in hot dry rocks requires the application of enhanced geothermal system (EGS) technology, which enables artificial enhancement of reservoir permeability and improved heat extraction efficiency. This study addresses the assessment of geothermal potential in the Gorzów Block (NW Poland), an area identified as prospective for a CO2-enhanced geothermal system (CO2-EGS). Geological modeling was used as the primary tool to integrate structural, petrophysical, and thermal data in order to reduce exploration uncertainty and identify the most favorable reservoir interval. The workflow included structural interpretation and parameter modeling of key reservoir properties, with particular emphasis on porosity, clay mineral content, permeability, density, and temperature distribution. The results indicate that the optimal reservoir zone is located at depths of 4100–4300 m below ground level within Lower Permian volcanic formations (Autunian). At this depth, reservoir temperature reaches approximately 145 °C. The analyzed rocks exhibit low porosity (0.04), moderate clay content (0.12), very low permeability (0.008 mD), and an average density of 2.59 g/cm3, indicating tight reservoir conditions requiring hydraulic stimulation. The assessment is subject to limitations associated with the availability and spatial distribution of subsurface data, as well as uncertainties inherent in geological and petrophysical modeling of deep formations. Therefore, the identified reservoir interval and estimated parameters should be regarded as a preliminary assessment that requires further verification through additional exploration and reservoir testing. Nevertheless, the study confirms the value of integrated geological modeling for identifying deep geothermal reservoirs and supporting decision-making in EGS site selection.