Carbon dioxide flooding

Carbon dioxide (CO₂) flooding is a process whereby carbon dioxide is injected into an oil reservoir in order to increase output when extracting oil.

When a reservoir’s pressure is depleted through primary and secondary production, Carbon Dioxide flooding can be an ideal tertiary recovery method. It is particularly effective in reservoirs deeper than 2,500 ft., where CO₂ will be in a supercritical state, with API oil gravity greater than 22–25° and remaining oil saturations greater than 20%. It should also be noted that Carbon dioxide flooding is not affected by the lithology of the reservoir area, but simply by the reservoir porosity and permeability, so that it is viable in both sandstone and carbonate reservoirs. Carbon dioxide flooding works on the physical phenomenon that by injecting CO₂ into the reservoir, the viscosity of any hydrocarbon will be reduced and hence will be easier to sweep to the production well.