液压抽油机动态特性分析

应用机械振动理论，对液压抽油机的动态特性进行了分析。结果表明，液压抽油机在准匀速悬点运动条件下，抽油泵的运动由两部分组成一是随悬点一起的刚体运动，二是由于悬点支撑位移激发的振动响应，其振动频率为系统的固有频率。适当调整系统参数，抽油泵将出现超冲程现象，这对于提高采油效率将是有益的。在准匀速悬点位移作用下，将引起抽油杆柱的振动，导致杆柱中的动应力。杆柱中的最大振动位移随深度增加量值逐渐增大，最大动应力随深度增加而逐渐减小。最大动应力随深度不是线性变化的，而是为二次函数关系。

Dynamic Analysis of Hydraulic Pumping Units

The dynamic analysis of hydraulic pumping units was carried out in this paper by using the theory of mechanical vibrations. The house-head movement of the pumping unit is mainly uniform,except the alternation period of upper-and down-strokes.Under the action of the house-head movement,the vibration of the system,the sucker-rod and,furthermore,the dynamic stress will be induced.The results indicate that the movement of the downhole pump includes two parts. One is the movement following the horse-head.The other is the dynamic response excited by the support movement.When the parameters of the system are selected reasonably,over-stroke of the pump will appear.This is because the movement of the hydraulic piston obeys a particular law.The maximum displacement increases,and the maximum dynamic stress decreases with depth.The changing of maximum dynamic stress with depth obeys quadratic law.