Effects of viscosity ratio, interfacial tension and flow rate on hysteric relative permeability of CO2/brine systems

The results clearly show that the steady-state relative permeability depends on the viscosity ratio and IFT of the CO2/brine system. Due to the low CO2 viscosity and flow rate, the residual saturation of brine is greater than 50%. The low end-point of the relative permeability of CO2 is associated with small viscous forces. In the CO2/brine system, these forces are normally smaller than the capillary force. The small viscous forces are caused by the injected CO2 having a much lower viscosity than brine. The viscous force increases with increasing flow rate, resulting in more efficient CO2 displacement.