CO2 Storage in the Carbonate-Siliciclastic System

The work presented here investigates mixed carbonate and siliciclastic sediments, which are present in many stratigraphic successions for CO2 flow simulation. Such a mixed sedimentary system can exhibit extensive lateral and vertical facies heterogeneity. We have conducted a range of 3D numerical simulations to study the impact of such systems on CO2 storage. The results indicate that the shape of the injected CO2 in the heterogeneous models is asymmetrical. The flow paths are dispersed which result in irregular plume shape. Although the amount of CO2 dissolved in the brine is higher in the homogenous model and models with lower proportion of carbonate, we believe that the storage security cannot be guaranteed. This is because CO2 laterally migrated longer distance under the caprock and leakage points may allow free CO2 to escape from the reservoir.