Representation of Geological Heterogeneities and Their Effects on Mineral Trapping During CO2 Storage Using Numerical Modeling

The representation of geological heterogeneities and their impact on mineral trapping during CO2 storage was examined using TOUGHREACT. A series of simulations with increasing degrees of geological complexity were constructed and input parameters associated with different rock types were varied within reasonable ranges. Grid spacing was refined to determine the sensitivity of the models to grid size. Initial results indicate that the use of realistic relative permeability and capillary pressure input parameters for heterogeneous rock types have a significant effect on the extent of mineral sequestration due to the control relative permeability and capillary pressure have over the distribution of CO2 and pH. Significant numerical dispersion can occur when heterogeneities are represented by single grid layers.