Directional displacement of non-aqueous fluids through spontaneous aqueous imbibition in porous structures

•Saturation patterns in porous media were analyzed experimentally and numerically.•The two-phase flow pattern is linked to a wettability profile within porous media.•The concept of wettability capacity distribution is introduced.•Two-ends-open cores exhibit different imbibition patterns at boundaries.•Hydromagnesite exhibits a directional saturation pattern for two-phase flow.