旋转抽油杆柱扭转振动固有频率分析

在对旋转抽油杆柱的扭转振动分析的基础上 ,给出了各阶扭转振动固有特性参数的计算式 .实例计算结果表明 :螺杆泵采油系统在 70 0～ 1 80 0 m的正常下泵深度时 ,常用的单级和二级抽油杆柱的前五阶扭转振动固有频率在 2 6～ 6 0 8r/min,覆盖了螺杆泵采油系统的工作转速区 (6 5～3 5 0 r/min) ,这完全不同于有杆泵采油系统 .指出 :在选定螺杆泵采油系统的工作转速时 ,应将杆柱的前五阶扭转振动固有频率对应的转速作为约束条件 ,以避开该转速范围 ;对于级次杆柱的高阶固有频率 ,由于其频率相对单级杆柱的增减幅值在 2 .1 %～ 5 .2 %之间 ,可近似按单级杆柱考虑 .文中提供的数据可以直接指导螺杆泵采油系统的杆柱组合与系统转速的匹配

Analysis of Twisting Vibration Eigenfrequencies of Rotary Sucher-rod String

On the basis of the analysis of the twisting vibration of rotary sucher-rod string, a formula of calculating every harmonic vibration eigenfrequency is presented. The calculated result of a instance shows that, when the setting depth of a pump is in the range of 700~1800m, five lower harmonic twisting vibration eigenfrequencies of a single-diameter or two-diameter sucher-rod string are in 26~608 r/min, in which the working rotary speed range (65~350r/min) of screw pump producing systems is completely included. This is different from the case of suck rod pump producing systems. Therefore, when the working rotary speed of a screw pump producing system is selected, not only are the base frequency but also the higher harmonic eigenfrequencies of the sucker-rod string considered. The higher harmonic eigenfrequencies of a two-diameter sucker-rod string can be approximately substituted with those of a correspondence single-diameter sucker-rod string because the difference between the former and the latter is only 2.1%~5.2%. The data in the paper can be used for guiding the matching of sucker rod combination with rotary speed of a screw pump producing system.