Abstract To increase productivity from crude oil reservoirs, carbondioxide (CO2) is usually injected during secondary and/or tertiary recovery. While CO2 injection significantly increases the amount of oil recovered, it causes asphaltene deposition at high concentrations. However, the presence of water reduces the extent to which asphaltene is precipitated. Thus, the aim of this report is to determine why the presence of water reduces the amount of asphaltenes precipitated during CO2 injections. Results from CT scan data on water and gas injections are also provided and are accompanied with scanned images.