Purpose

The coupled axial-transverse nonlinear vibration simulation model of sucker rod sting (SRS) in deviated wells is established. Based on the simulation results, the nonlinear vibration phenomenon of SRS is analyzed, and the influence of centralizer arrangement on the nonlinear vibration of SRS is discussed.

Method

The mechanical simulation model of the coupled axial-transverse vibration of SRS in deviated wells can be simplified to the coupled axial-transverse vibration model of longitudinal and transverse curved beam with initial bending under borehole constraints. In this paper, when establishing the simulation model of the coupled axial-transverse vibration of SRS, it is proposed that the bending borehole trajectory is a main excitation of the vibration of SRS. Based on the theory of elastic vibration, a nonlinear dynamic simulation model of the coupled axial-transverse vibration of SRS in deviated well is established. Then the fourth-order Runge–Kutta method is used to solve the simulation model. The nonlinear vibration phenomenon of the SRS is studied by example analysis.

Results and conclusion

The simulation results show that: (1) the simulation curve of polished rod dynamometer card is in good agreement with the test curve, and the error value of polished rod maximum load and minimum load is within 5%, which shows that the coupled axial-transverse vibration simulation model of SRS established in this paper has high accuracy. (2) When the centralizer is not arranged, the chaotic motion of SRS mainly occurs in the compression section of SRS, which shows that the instability of SRS is the main reason for the chaotic motion of SRS. (3) The arrangement of centralizer can improve the bending rigidity of SRS, restrain or even eliminate the chaotic motion of SRS.

中文翻译：

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斜井抽油杆柱轴向横向非线性耦合振动研究

目的

建立了偏井抽油杆st（SRS）轴向-横向耦合非线性振动仿真模型。基于仿真结果，分析了SRS的非线性振动现象，并讨论了扶正器布置对SRS非线性振动的影响。

方法

可以将偏井中SRS轴向-横向耦合振动的力学模型简化为在井眼约束下具有初始弯曲的纵向和横向弯曲梁的轴向-横向耦合振动模型。本文在建立SRS轴向横向振动耦合仿真模型时，提出弯曲井眼轨迹是SRS振动的主要激励因素。基于弹性振动理论，建立了偏井中SRS轴向横向耦合振动的非线性动力学仿真模型。然后使用四阶Runge-Kutta方法求解仿真模型。通过实例分析研究了SRS的非线性振动现象。

结果与结论

仿真结果表明：（1）抛光棒测功机卡的仿真曲线与试验曲线吻合良好，抛光棒最大载荷和最小载荷的误差值在5％以内，表明轴向耦合建立的SRS横向振动仿真模型具有较高的精度。（2）当不设置扶正器时，SRS的混沌运动主要发生在SRS的压缩段，这表明SRS的不稳定性是SRS混沌运动的主要原因。（3）扶正器的布置可以提高SRS的抗弯刚度，抑制甚至消除SRS的混沌运动。