Fig.1 Microscale porous media model in VOF method

Fig.2 (a) Image segmentation processing; (b)Pore medium model; (c)Simulation of two-phase flow

Fig.3 Stratified two-phase flow between two parallel plates

Fig.4 Simulated andante section velocity and theoretical result

Fig.5 Capillary imbibition model

Fig.6 Simulation results of capillary imbibition model and theoretical results

Fig.7 Occurrence forms of residual oil in super high water cut stage (a) cluster residual oil; (b) porous residual oil; (c) drop residual oil; (d) columnar residual oil; (e) membranous residual oil

Fig.8 Recovery percent of reserves curve under different wettability

Fig.9 Remaining oil distributions under different wettability

Fig.10 The occurrence of (a) membranous residual oil; (b) drop residual oil

Fig.11 Distributions of remaining oil at different viscosity of crude oil (1 represents oil, 0 represents water.)

Fig.12 Effects of crude oil viscosity on oil recovery

Fig.13 Water cut at outlet in oil-water two-phase flow model

Fig.14 Recovery percent of reserves curve under different displacement velocities

Fig.15 Distributions of remaining oil at different displacement velocities

Fig.16 Schematic of cylindrical residual capillary effect in equal diameter cylindrical orifice

Fig.17 Pressure difference between P1 and P2 (columnar residual oil displacement process)

Fig.18 Enlarged view of local displacement process at ② in Fig. 15

Fig.19 Enlarged view of local displacement process at ③ in Fig. 15

Fig.20 Pressure difference curve at both ends of f3 directional columnar remaining oil

Fig.21 Recovery percent of reserves curve under different displacement directions

Fig.22 Remaining oil distributions in different displacement directions

Fig.23 Velocity distributions in different displacement directions

Fig.24 Enlarged view of local flow field (blue line) at ④ in Fig. 22