CO₂ mineral sequestration mechanisms and capacity of saline aquifers of the Upper Silesian Coal Basin (Central Europe) - Modeling and experimental verification

Significant part of CO₂ emissions from industrial sources in Central Europe originates from the territory of the Upper Silesian Coal Basin (USCB). This paper presents a study of the suitability of saline aquifers within the USCB, as potential greenhouse gas repositories.Evaluation of mineral-trapping mechanisms and assessment of storage capacity of the aquifers is based on hydrochemical modeling and experimental tests of rock-water-gas interactions.Two stages of modeling enabled prediction of the immediate changes in the aquifer and insulating rocks impacted by the beginning of CO₂ injection, and the assessment of long-term effects of sequestration. In the analyzed sandstone aquifers the minerals able to trap CO₂ are dawsonite and dolomite, while siderite or calcite are able to degrade. The phases capable of mineral CO₂ trapping in the cap rocks are: dawsonite, dolomite, and siderite. Mineral-trapping capacity, for the sandstone aquifers is relatively low: 1.2 to 1.9 kgCO₂/m³, with the exception of the Upper Silesian Sandstone Series - over 6.6 kgCO₂/m³. The solubility trapping capacity does not exceed 4.07 kgCO₂/m³.