聚驱抽油杆载荷计算方法研究

聚合物驱技术在提高油田采收率的同时,带来了抽油杆严重偏磨的问题。在分析聚驱产出液黏度变化和流变特性的基础上,运用计算流体动力学(CFD)方法模拟抽油杆下行过程中杆管环空的流体流动,得到液体阻力随抽油杆运动速度的变化。引入流体修正系数1.58修正水驱计算式;另外,分段拟合了液体通过游动阀产生的阻力曲线,方便抽油杆柱的载荷分布计算。通过对10口井共30种工况下的抽油杆载荷进行计算,比较了实测数据,得到井口处最大、最小载荷的最大偏差分别为7.31%、13.34%。认为两者间具有较好的吻合性,较好地验证了计算方法的可靠性,为聚合物驱抽油杆的防偏磨设计计算打下了基础。

Research on load calculation of sucker rod for Polymer flooding

Polymer flooding technology is useful for the recovery in the oil field and brings the serious problem of partial wear of sucker rod simultaneously. In this paper, the viscosity and rheological properties of poly produced fluid are investigated, and the computational fluid dynamics (CFD) method is used to simulate the rod tube annulus fluid flow. Through investigating the fluid resistance changed with the sucker rod movement speed, the water flooding calculation formula is fixed with the correction coefficient of 1.58. In addition, the resistance curve of liquid through traveling valve is piecewise fitted for the convenience of load calculation. Furthermore, the sucker rod loads are computed at total of 30 cases of 10 wells to shows the maximum deviations of the maximum and minimum load are 7.31% and 13.34% respectively, which shows a consistency between calculation and test. This study verifies the reliability of the calculation method and provides a foundation for wear preventing design of polymer flooding rod.