On　the　basis　of　self-designed　and　built　pipeline　system　of　drag　reduction　on　water　annulus　transportation　of　heavy　oil,　the　flow　resistance　characteristics　of　heavy　oil　simulated　by　500#　white　oil　under　the　action　of　water　ring　in　horizontal　pipe　were　experimentally　studied.　The　influence　of　0.3-1.0m/s　oil　superficial　velocities,　0.11-0.72m/s　water　superficial　velocities　and　0.13-0.49input　water　volume　fractions　on　the　flow　patterns　characteristics　and　drag　reduction　effect　of　water　lubricated　pipe　flow　was　analyzed.　The　experimental　results　showed　that　the　oil-water　two-phase　flow　exhibits　a　typical　eccentric　annular　flow　pattern,　where　the　annular　water　film　can　effectively　isolate　and　lubricate　the　interface　of　oil　phase　and　pipe　wall.　The　pressure　drop　in　the　process　of　pipeline　transportation　can　be　substantially　reduced　by　the　water　ring　transportation,　which　is　only　1/55-1/27　of　the　pressure　drop　when　the　oil　is　delivered　separately　under　the　same　oil　flow　rate.　The　oil　transportation　efficiency　was　in　a　high　level,　which　was　all　above　40,　when　input　water　fraction　is　in　the　range　of　0.13-0.27.　With　the　increase　of　oil　superficial　velocity　and　water　input　fraction,　the　pressure　drop　per　unit　pipe　length　increases,　while　the　drag　reduction　effect　and　oil　delivery　efficiency　of　water　annulus　conveying　decrease.　©　2021,　Chemical　Industry　Press　Co.,　Ltd.　All　right　reserved.