钻铤柱长度及减震器位置对ZJ45J钻机钻柱振动的影响

本文建立了钻机—钻柱—减震器振动系统的力学模型及其运动方程,求得了钻铤柱不同长度和减震器不同位置对钻柱纵振影响的数值,因而发现:钻铤柱长度的改变仅对系统纵振的固有低频产生明显影响;钻柱振动位移亦随钻铤拄长度增加而增加;还发现钻柱固有纵振与固有扭振具有同时激励的可能;证实了减震器的效果以安装于钻机与钻柱之间较为理想,它既降低了转盘临界转速,又减小了各部分振动位移。最后指明了使用变刚度弹力阻尼减震器的方向.

The Effect of Drill Collar String Length and the Position of an Absorber on Drilling Stem Vibration of Model ZJ45J Rig

Reducing drilling stem vibration can evidently better the economical benefit in drilling. The mechanical model of drilling rig-drilling stem vibration absorber system is de fined and the motion differential equation is set up in this paper. Through a lot of calculations the numerical values are obtained, which represent the effects of the length of drill collar string and the installing position of a vibration absorber on longitudinal vibrauon performance of the drilling stem. It is found that variation of drill collar string length exerts an evident influence only on the low natural frequency of the system's longitudinal vibration, and the increase of the drilling collar string length leads to greater vibration displacement, it's possible for drilling stem's natural longitudinal and torsional vibration to be excited at the same time. It is proved that the best results can be obtained when the vibration absorber is installed between the rig and the drilling stem, because in this way the critical rotary speed of the rotary tabk is reduced and the vibration displacement of all parts are decreased; besides, a way of using elastisity-damping-vibration absorber with a changing rigidity has been shown. In this paper, all kinds of absorbers are compared for their merits and demerits.