钻柱纵振固有频率与钻机转速之间的关系

Relationship between the Natural Frequency of Drill String Longitudinal Vibration and the Speed of Drilling Rig

井内钻柱振动会对钻进效率带来极大影响,而合理的钻机转速是从激振频率角度减小钻柱振动的有效方法之一。通过ANSYS建立了金刚石绳索取心钻井钻柱有限元模型,分析了钻柱纵振固有频率随井深变化趋势,并研究了钻柱纵振固有频率与引起钻柱共振的临界转速之间的关系;综合分析了钻井深度、钻柱固有频率、钻机转速之间的联系,在其基础上预测了各段井深钻进时所应避开的钻机转速,为实际钻进过程中合理的转速选取提供了理论依据。

The vibration of drill string in the well greatly affects the drilling efficiency,and reasonable rotating speed of the drilling rig is one of the effective methods to reduce the vibration of drill string from excitation frequency level.Setting up the finite element model of drill string of diamond wire-line core drilling by ANSYS,this paper anlyses the relationship between natural frequency of drill string longitudinal vibration and the well depth and then studies the relationship between the natural frequency of drill string longitudinal vibration and the critical speed which causes drill string resonance.Comprehensively analysis is conducted to determine the relationship between the drilling depth,the natural frequency of the drill string and the rotating speed of the drilling rig on the basis of the above analysis for predicting the rotating speed of the drilling rig which should be avoided while drilling.This study provides theoretical basis for reasonable rotating speed selection at the drilling process and suggests that with drill string resonance,rotating speed of the drilling rig should be adjusted in a reasonable range so as to avoid effectively the drill string vibration.