CO2 miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties

Miscible CO2 injection process has become widely used technique for the enhanced oil recovery in low permeability reservoirs. Core flooding experiments and field test of CO2 miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties was studied. The results showed that CO2 miscible flooding in low permeability sandstone reservoirs can enhance oil recovery both in laboratory study and field test. The permeability of sandstone reservoirs decreased during CO2 miscible flooding due to the precipitation of asphaltene of crude oil. The precipitation of asplialtene lead to a reduction of asphaltene content and the apparent viscosity of crude oil. A further study on inhibitors and removers for asphaltene deposits from crude oil should be investigated to prevent and remove asphaltene deposits in low permeability sandstone reservoirs.