Lattice Boltzmann Method Simulation Of Carbon Dioxide Foam Flooding In Porous Media

Carbon dioxide foam flooding technology is an innovative technology to enhance oil recovery,which can significantly improve sweep efficiency and displacement efficiency of low permeability reservoir.CO₂ foam flooding technology has the vast development foreground.The displacement is a complex fluid dynamic problem related to multi-component multi-phase flow and flow in porous media.The process of CO₂ foam flooding was simplified to immiscible displacement in single pore and porous media model in this paper.The process was simulated based on Shan-Chen pseudopotential model in lattice Boltzmann method.The effect of various factors on the displacement flow was investigated,aiming to choosing the optimal displacement conditions for different reservoirs.The relationship between liquid-liquid interaction,solid-liquid interaction and surface tension,surface wettability was coupled with Shan-Chen pseudopotential LBM model.The displacement in single pore and porous media model was numerically simulated.Single pore simulation results show that phase interface becomes smoother,and the sweeping efficiency and displacement efficiency become greater with the decrease of flow time,Re number and Ca number.Better surface wettability and higher viscosity ratio of displacing fluid to displaced fluid result in the same effects,and viscous fingering phenomenon can be controlled.When the gravity is considered,the interface front has a tendency of moving along the direction of gravity,and the displacement efficiency decreases slightly,which can be negligible.While in porous media,displacing phase rounds solid frames,merges,and advances to displace.The effect on displacement efficiency of displacement time,Re,surface wettability and gravity in porous media is consistent with the laws in single pore.The change of Ca number and viscosity ratio has little impact on displacement efficiency,which is affected by complex inner structure of porous media.Research results above show that foam preparation and injection rate should be considered according to reservoir conditions and physical properties of CO₂ foam to ensure the application of CO₂ EOR technology successfully.