Predicting the Interactions of H2S-CO2 Mixtures with Aquifer Rock, based on Experiments and Geochemical Modeling

Greenhouse effect prevention, oil and gas stimulation, and other recent technologies require a recognition of the acid gas interactions with geologic formations. The experimental study coupled with hydrogeochemical modeling was focused on the impact of CO2, H2S and their mixtures on the formations of the Upper Silesian Coal Basin. Significant changes in structure and composition of rock samples influenced by acid gas were identified in autoclave experiments. Skeletal grains dissolution was most intense in carbonates and chlorite, and caused an increase of porosity. In the case of geological storage of H2S, a release of significant amounts of CO2, from dissolution of primary carbonates should be expected, as demonstrated the results of modeling.