钻柱系统粘滑振动稳定性分析及减振方法探讨

STABILITY ANALYSIS OF STICK- SLIP VIBRATION AND DISCUSSION OF VIBRATION REDUCTION METHOD OF DRILL STRING SYSTEM

随着深井、超深井的发展,钻柱系统粘滑振动严重影响着钻井速度、钻井成本和钻井安全。钻头切削岩石的摩擦力是钻柱系统发生粘滑振动的主要因素。针对钻头切削岩石的实际工况,分析了钻头—岩石的切削模型,建立了其相互作用的摩擦模型,得出钻头处扭矩随转速的变化趋势。从能量守恒出发,分析了钻柱系统粘滑振动的稳定性,计算得出了钻柱系统粘滑振动稳定时的临界钻压。将临界钻压公式描绘成钻柱振动状态的钻压—转盘转速关系图,并在此基础上探讨了粘滑振动的减振方法,以期为钻井过程中减少钻柱的粘滑振动提供参考。

With the development of deep well and ultra-deep well,the stick- slip vibration of drill string system seriously affects the drilling speed,drilling cost and drilling safety. The friction of the bit cutting rock is the main factor which caused drill string stick- slip vibration. Aimed at the actual working condition of the bit cutting rock,the cutting model of bit and rock was analyzed,the friction model of interaction between them was established,and the relation between the torque and rotation speed was obtained. Starting from conservation of energy,the stability of the stick- slip vibration of the drill string system was analyzed,and the critical weight on bit of the stable fully developed stick- slip vibration was calculated. The pressure- rotary speed graph of the stick- slip vibration states was portrayed for the critical drilling pressure,and the reduction methods were discussed based on it,attempting to provide the reference for reducing stick- slip vibration of the drill string during drilling process.