A lubricating element for drag reduction in production and transportation of water-cut heavy oil in a wellbore comprises a flow guide component and a shell component; the flow guide component is fixed in a cyclone chamber of the shell component, and is provided with an intermediate rod to connect and fix a center cone, a flow stabilizing cone and flow guide blades. The lubricating element is a static element integrating three functions of oil-water separation, water control and liquid ring formation, thereby reducing energy consumption for production and transportation of heavy crude oil, and cutting down surface water treatment facilities.