Study on Distribution Characteristics and Displacement Mechanism of Microscopic Residual Oil in Heterogeneous Low Permeability Reservoirs

Figure 6

Distribution of residual oil under polymer surfactant flooding with a permeability ratio of 9 (① cluster, ② oil drop, ③ oil film, ④ columnar, and ⑤ blind end; the red part represents oil; the blue part represents the displacement fluid; the injection direction of the displacement agents is from right to left).