Technical feasibility and application effect of coupled CO2 sequestration and EOR in tight sandstone oil reservoir

This paper focused on the technical researches on CO2 sequestration and enhancing oil recovery by CO2 flooding. Experiments and numerical reservoir simulation were conducted to study the technical feasibility and application effect of implementing CO2 sequestration and EOR in tight sandstone oil reservoirs. Small maximum pore throat radius, inefficient mercury withdrawal and large residual volume in pore together implied that the bad connectivity among pores would result in high percolating resistance in reservoir. Several conclusions were obtained at last - the physical properties of the oil are favourable for conducting CO2 sequestration and EOR; miscible flooding performs better than immiscible flooding; CO2 sequestration and EOR are easier to be implemented in the reservoirs with preferable homogeneity. A technology combining WAG with profile modification was adopted to maximise the ability of CO2 injection and oil-producing for single well so that the benefit of CO2 sequestration and EOR can be improved more efficiently.