Preliminary geochemical modeling of water–rock–gas interactions controlling CO₂ storage in the Badenian Aquifer within Czech Part of Vienna Basin

Prediction of hydrogeochemical effects of geological CO₂ sequestration is crucial for planning an industrial or even experimental scale injection of carbon dioxide gas into geological formations. This paper presents a preliminary study of the suitability of saline aquifer associated with a depleted oil field in Czech Part of Vienna Basin, as potential greenhouse gas repository. Two steps of modeling enabled prediction of immediate changes in the aquifer and caprocks impacted by the first stage of CO₂ injection and the assessment of long-term effects of sequestration. Hydrochemical modeling and experimental tests of rock–water–gas interactions allowed for evaluation of trapping mechanisms and assessment of CO₂ storage capacity of the formations. In the analyzed aquifer, CO₂ gas may be locked in mineral form in dolomite and dawsonite, and the calculated trapping capacity reaches 13.22 kgCO₂/m³. For the caprock, the only mineral able to trap CO₂ is dolomite, and trapping capacity equals to 5.07 kgCO₂/m³.