The ultimate goal of this research was to experimentally evaluate the change in a number of multiphase flow characteristics of the system over time caused by the potential chemical and physical/mechanical processes occurring during deep CO2 disposal. In order to achieve this goal the effects of cyclic/alternating CO2-brine flooding, flow direction, existence of residual hydrocarbon (natural gas) and change in the reservoir stress field on the system’s multiphase flow behaviour were investigated. Until completion of this study there were no experimental data published in the literature addressing the above mentioned issues and the results obtained, and published within this thesis were the first of their kind.