CO2 capture and storage is one of the most important ways to reduce greenhouse emissions and thus reduce the increase of the world average temperature. Deep saline aquifers are suitable geological formations for CO2 underground storage in a permanent and safe way. Among the different trapping mechanisms, residual CO2 trapping indicates the trapping of the injected carbon dioxide inside the rock pores thanks to capillary forces. Residual CO2 saturation when the CO2 plume migrates through the aquifer cannot be predicted and must be assessed experimentally. The Capillary Desaturation Curve obtained from laboratory data is the most used plot to evaluate the residual CO2 saturation as a function of the Capillary number, expressing the ratio of viscous to capillary forces.