A mathematic model of anothite dissolution in CO₂ solution

This chapter focuses on the study on the dynamics occurred at the interface among cap rocks, Anorthite, and CO₂ solution because of CO₂ geological sequestration. The efficient CO₂ sequestration in the underground reservoir is mostly dominated by the porous structure of the cap rocks that are either essentially impermeable strata such as thick rock salt layers (aquicludes) or with lower permeability such as shale rocks and mudstones (known as aquitards). With basis on the fundamental theories of geochemistry and mass transfer, a mathematical model of Anothite dissolution in CO₂ solution is developed for describing the dynamics of interface chemistries and transport physics. The model developed is convenient to be implemented into the existed geo-hydrological numerical model for simulating the long-term CO₂ geological sequestration performance. The preliminary results obtained from the model analysis shows that Anorthite dissolution in a CO₂ solution is mostly dominated by chemical reaction rather than the mass transfer when local Sherwood number is larger than 5 and temperature is lower than 325K. For the environment of the CO₂ geological sequestration at depth about 1000m, temperatures range from 313 to 338K, the dissolution may be governed alternatively by chemical reaction or by fluid mass transfer depending on the variation in local Sherwood number.