Abstract: The research on oil-water migration and accumulation plays an important role in understanding reservoir forming regularities,as well as guiding oil and gas exploration.As an important influence factor in oil-water migration,surface tension may act as driving force or resistance of oil-water displacement,depending on the geometric shape differences of the migration channels.A numerical simulation of oil-water displacement in the capillary channel has been made by using the surface regular protuberances for simulating the rough elements,using the unsteady Navier-Stokes equation with volume of fluid(VOF) interface tracking method and the continuum surface force(CSF) model for the surface tension.The results show that the shape and size of the rough element have important effect on the shape of oil-water interface and the mass flow rate;and when driven by surface tension,water phase can be wrapped by oil phase around the throat formed by rough elements,whereas oil may flow separately in water phase when driven by the entrance pressure.