Using the Konary anticlinal structure in central Poland as an example, a geological model has been built of the Lower Jurassic reservoir horizon, and CO2 injection was simulated using 50 various locations of the injection well. The carbon dioxide storage dynamic capacity of the structure has been determined for the well locations considered and maps of CO2 storage capacity were drawn, accounting and not accounting for cap rock capillary pressure. Though crucial for preserving the tightness of cap rocks, capillary pressure is not always taken into account in CO2 injection modeling. It is an important factor in shaping the dynamic capacity and safety of carbon dioxide underground storage. When its acceptable value is exceeded, water is expelled from capillary pores of the caprock, making it permeable for gas and thus may resulting in gas leakage. Additional simulations have been performed to determine the influence of a fault adjacent to the structure on the carbon dioxide storage capacity.

The simulation of CO2 injection into the Konary structure has shown that taking capillary pressure at the summit of the structure into account resulted in reducing the dynamic capacity by about 60%. The greatest dynamic capacity of CO2 storage was obtained locating the injection well far away from the structure’s summit. A fault adjacent to the structure did not markedly increase the CO2 storage capacity. A constructed map of CO2 dynamic storage capacity may be a useful tool for the optimal location of injection wells, thus contributing to the better economy of the enterprise.

Nowadays, hydrogen is considered a potential successor to the current fossil-fuel-based energy. Within a few years, it will be an essential energy carrier, and an economy based on hydrogen will require appropriate hydrogen storage systems. Due to their large capacity, underground geological structures (deep aquifers, depleted hydrocarbon fields, salt caverns) are being considered for hydrogen storage. Their use for this purpose requires an understanding of geological and reservoir conditions, including an analysis of the preparation and operation of underground hydrogen storage. The results of hydrogen injection and withdrawal modeling in relation to the deep Lower Jurassic, saline aquifer of the Konary geological structure (trap) are presented in this paper. A geological model of the considered structure was built, allowable pressures were estimated, the time period of the initial hydrogen filling of the underground storage was determined and thirty cycles of underground storage operations (gas injection and withdrawal) were simulated. The simulations made it possible to determine the essential parameters affecting underground hydrogen storage operation: maximum flow rate of injected hydrogen, total capacity, working gas and cushion gas capacity. The best option for hydrogen storage is a two-year period of initial filling, using the least amount of cushion gas. Extracted water will pose a problem in relation to its disposal. The obtained results are essential for the analysis of underground hydrogen storage operations and affect the economic aspects of UHS in deep aquifers.