Tough2-Eco2n Simulation
Based on preliminary data, we examine the storage of 0.2 kg/s of CO2 per meter for 50 years, followed by 450 years of post-injection monitoring stage, in the Lakota and Dakota formations, using TOUGH2-ECO2N numerical simulator. The Lakota and Dakota formations have the thickest sandstone layers, and their pore-water salinity is >10,000 ppm. The model mesh is designed with refined grid near to the well, starting with 0.01 m and become coarser at increasing distance with a total of 39 gridblocks to reach 1,000 km. In the z-direction we initially used 1 m increment blocks. After 50 years of injection, preliminary modeling indicated a total mass of 15 Mt CO2 would be stored in the model; 11.5 in the Lakota Formation, 3.3 Mt in the Dakota Formation, and <0.4 Mt within the sealing units (Fuson and Skull formations). Post injection, we believe more SC-CO2 will be dissolved and trapped in aqueous phase. The possible loss of post-injection CO2 from the Lakota Formation appears to be an indication to the poor sealing ability of the Fuson Formation. Even though CO2 migrates through the Fuson and Skull formations (a modeling breakthrough is evident in both sealing units after several hundred years of injection), there are several hundred meters of overlying seals (not modeled here) that will contain the CO2.
