oil displacement effi-ciency 基本例句 驱油效率 Comparing with water flooding,the viscoelasticity of polymer flooding is favorable for improving the sweep efficiency of reservoirs,but it is limited to enhance oil recovery.与注水工艺相比，聚合物所具有的粘弹性能提高驱油效率，但其对提高采收率的贡献是有限的。