Co-injection case after 0.25 PV of surfactant solution injection, with M_ref,x = 500, K_ref,x = 100 mD, V_DP = 0.75 and K_z/K_x = 0.1. Left: scaled M_ref,x with L_z = 10 m. Solid and dashed lines stand for horizontally and vertically averaged profiles, respectively. Center: scaled M_ref,x with L_z = 5 m. Right: comparison of horizontally averaged profiles without (“ref”) and with (“mod”) M_ref,x scaling (“L_z” and “L_z/2” stand for L_z = 10 and 5 m, respectively).