Analysis of CO2 Migration in Horizontal Saline Aquifers during Carbon Capture and Storage Process

Abstract

The storage of CO2 has become an important worldwide problem, considering that an excess of CO2 in the Earth’s atmosphere causes dramatic changes in its climate. One possible solution is to remove the excess of CO2 from the atmosphere, capture it in the process of creation, and store it safely, negating the possibility of its return into the atmosphere. This is the process of Carbon Capture and Storage (CCS). In the following paper, the authors investigate horizontal saline aquifers and their ability to store CO2. The authors’ application of sensitivity analysis on horizontal migrations uncovered that CO2 permeability and aquifer porosity have a considerable impact on horizontal migrations. During the migration process, CO2 can reach tens of kilometers from its injection point. By introducing effective CO2 density to the conduction velocity term, the authors showcase that the convection-diffusion equation for compressible fluids can be replaced with the equation for incompressible fluids. The buoyancy factor in convective velocity is as density dependent as in conduction velocity. By means of introducing an effective density to the aforementioned term, the process of transport via variable convective velocity can be substituted for a process which is effective, constant, and not density dependent.