Effect of reactive surface area of minerals on mineralization due to CO2 injection in a depleted gas reservoir

In this research, long-term (up to 1000 years) geochemical modeling of subsurface CO2 storage was carried out on Permian Rotliegend reservoirs of depleted gas fields in northeast Netherlands. The results showed that mineral dissolution/precipitation has a minor effect on reservoir porosity. In order to validate this, we focused on the reactive surface area of minerals which we measured by scanning electron microscopy. These calculations resulted a range of surface area values for each mineral which were subsequently subjected to a parameter analysis and Monte Carlo uncertainty analysis. These analyses revealed that in the Rotliegend sandstones, the surface area of quartz has by far the largest effect on SMCO2 (total amount of CO2 sequestered as mineral). Mineral trapping of CO2 increased significantly with increasing quartz surface area. This leads to the conclusion that CO2 injection in a sandstone reservoir with fine grained quartz has a higher potential for mineral trapping of CO2. In addition, using parameter analysis we also could determine the effect of surface area of each mineral on its own dissolution/precipitation mechanisms as well as on the other minerals. For example, our results showed that dawsonite precipitation is proportional to kaolinite and K-Feldspar surface area.