Abstract: Water-annulus technology is the most economical method for the transportation of heavy oil through a pipeline, wherein the water occupies the region of high shear rate next to the pipe wall and forms a lubricating annular layer. As the oil does not touch the wall, mthe friction loss in the pipeline is far less than that of transporting oil alone. This method is particularly suitable for transporting highly viscous or high pour point crude oil, which will be otherwise difficult to transport. This paper explains in detail the effect of flow state, parameters of the water annulus on transport efficiency. An equation is obtained for calc-ulating the critical velocity of the visco-elastic annular water in laminar flow. The optimum average velocity and the oil/water ratio are derived. When the annular water is in laminar flow, the optimum oil/water ratio is 2 (33% water), while in turbulent flow it is approximately 9 (10% water). The optimum ratio could be taken in range of 4 to 6 (14～20%), if the flow state cannot be ascertained. The optimum average velocity is equal to or slightly higher than the critical velocity of the laminar water annulus. In general, this value is selected in the range from 0.5 to 1.5 m/s. The theoretical results mentioned above conform to experimental data for test loops of 15, 50, 203Dg, which means that our conclusions can be applied to transporting oil in pipelines of different diameters.

摘要： “水环”输油工艺是管输重油的最经济的方法。它是让水充满紧靠管壁的高剪切区,形成一层薄的环形滑润层,使油不能与管壁接触,因此比单独输送同样油的摩擦损失小得多。输油效率很高,特别适于输送其它方法难以输送的高粘或高凝原油。本文阐述了水环的不同流态和各种参量对输油效率的影响,找到了计算粘弹性层流水环临界速度的表达式,导出了使输油效率最高的最佳平均速度和最佳油水比(含水量)。层流水环的最佳油水比为2(含水量33%);湍流水环的最佳油水比约为9(含水量约10%)。若不知道水环处于什么流态,则最佳油水比可取为4～6(含水量14～20%)。最佳平均速度等于或略大于层流水环的临界速度,通常在0.5～1.5米/秒内选取。上述理论结果与Dg15、Dg50和Dg203水环试验数据一致。说明上述结论可以在不同管径管道的水环输油实践中应用。