Abstract: Corrosion products caused by accumulated water in low places of the product oil pipeline often lead to trunk line equipment blockage.It is an effective method to reduce the corrosion of product oil pipeline and prevent the pipeline blockage by oil flow shear to flush the accumulated water in low places and discharge it out of the pipeline.The research progress on the accumulated water flow characteristics, the accumulated water movement speed, the critical conditions under which accumulated water can be displaced, the influencing factors and rules of critical conditions were summarized, from the aspects of experimental research, theoretical analysis and numerical simulation.The existing problems in the current research were analyzed, and it was proposed that the experimental research on the distribution characteristics and movement speed of accumulated water should be carried out in a wider speed range(0.57–1.53 m/s).In addition, the critical conditions for the transformation from pipes pre-wetted with water to constant oil-wetting pipes should also be studied.The research results have guiding significance to discharging the accumulated water and impurities.