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钻柱振动的固有频率是钻柱在给定钻具组合（ＢＨＡ）条件下钻柱振动的固有特性，在钻进过程中钻头与地层相互作用对钻柱产生激励振动，如果某一激励频率与钻柱自身的固有频率相近时，钻柱将产生共振现象．共振对钻柱是有害的，它可以引起钻柱局部的应力集中，导致钻柱断裂，发生井筒事故．共振与钻井参数有直接关系，如钻压、转盘转数、泥浆性能等，因此，通过调整钻井参数可以避免钻柱的共振现象，达到优化钻井的目的．给出了钻柱轴向振动的固有频率和振动传输公式．现场测量及计算表明，不是所有的固有频率点都会引起钻柱的强烈振动，它取决于振动传输比，现场试验数据验证了计算公式．通过固有频率的计算，分析了减震器对固有频率的影响以及固有频率随井深增加的变化趋势．
The natural frequency of the drill string vibration is the inherent characteristic of the drill string vibration under a given drilling tool combination (BHA). During the drilling process, the drill bit interacts with the formation to generate excitation vibration to the drill string. If an excitation frequency and When the natural frequency of the drill string is similar, the drill string will produce the resonance phenomenon. Resonance is detrimental to the drill string, which can cause localized stress concentration on the drill string, resulting in a break in the drill string and a wellbore accident. Resonance is directly related to drilling parameters, such as weight-on-bit, turntable rotation, mud performance, etc. Therefore, by adjusting the drilling parameters, the resonance of the drill string can be avoided and the purpose of drilling optimization can be achieved. The natural frequencies and vibration transmission formulas of drill string axial vibration are given. Field measurements and calculations show that not all natural frequency points cause strong vibration of the drill string, which depends on the vibration transfer ratio. Field test data verify the formula. Through the calculation of the natural frequency, the influence of the shock absorber on the natural frequency and the change tendency of the natural frequency with the increase of the well depth are analyzed.