钻柱纵向振动的计算

钻井过程中钻具失效问题严重。本文在理论分析的基础上,对纵向振动进行了较好的数值分析。研究表明,整体钻柱纵向振动特性受钻柱规格以及长度影响。长度增加,钻柱相应各阶固有频率显著降低。纵向振动还与钻铤的长度有关,当钻铤长度增加时固有频率略有下降。计入钻井液附加质量效应后,钻柱的各阶固有频率显著降低。分析表明,钻井液阻尼对钻柱动力安全性有一定的积极意义。

Calculation of Longitudinal Vibration of Drill String

The problem of BHA’s failure is serious.Based on theory study,detailed numerical simulation on properties of the drill string was done in this paper.The results show that the property of axial vibration changes while the string dimension and the length of drill string change.The axial vibration natural frequence changes small while the Drill Collar length increases.Due to the influence of the drilling fluid the natural frequency becomes lower.Analysis shows that drilling fluid damper have a certain positive significance on the drill string security.