Recovery performance and relative permeabilities of composite cores

Abstract

An experimental and numerical investigation was carried out ot study the recovery performance and the averaging process of relative permeabilities of composite cores. The displacement experiments were conducted using carbonate reservoir rock samples. The results indicated that the oil recovery obtained from the composite cores was less than that obtained form the individual core plugs. The observed decrease in oil recovery is attributed to viscous fingering and bypassing due to the heterogeneous nature of the carbonate rocks. The relative permeabilities of the composite cores did not represent any kind of average of the individual plugs relative permeabilities. The numerical simulation results results showed that the oil recovery of the composite core is the average of the individual plugs recoveries. The relative permeability of the composite core is the harmonic average of the relative permeabilities of the individual plugs and the ordering of the plugs making the composite had no effect on the calculated average relative permeability curves.