深井钻柱粘滑振动特性分析

粘滑振动严重影响钻柱系统的机械钻速,进而增加钻井成本,影响完井周期。为研究深井钻柱系统的粘滑振动特性,采用集中参数模型,通过钻头与岩石相互作用原则,既考虑钻头的摩擦作用,又考虑钻头的切削作用,建立钻柱系统轴向和扭转的耦合振动无量纲控制方程。基于MATLAB/Simulink软件对钻柱系统振动响应进行数值求解,分析了无量纲化控制参数,即转盘角速度、钻压以及粘性阻尼比、刀翼数对钻柱粘滑振动特性的影响。结果表明,确定的钻柱结构和系统参数存在发生粘滑振动的临界值,增大转盘转速、减小钻压、增大阻尼比到临界值时,钻头粘滑振动消失,同时增加刀翼数也会使粘滑振动得到抑制。

Analysis of Stick-slip Vibration Characteristics of Deep Well Drill String

Stick-slip vibration of drill string system seriously affects the rate of penetration, increases drilling cost and influences the completion period accordingly. A lumped parameter model was adopted to investigate the characteristics of the stick-slip vibration of the drilling system. The drill string system axial and torsional coupled vibration of the dimensionless governing equations was established through the principle of bit/rock interaction with the overall consideration of friction effects, as well as the cutting effect of the drill bit. The effects of dimensionless control parameters, including the angular velocity of the rotary, the weight on bit, viscous damping ratio and the number of blades on the stick-slip vibration of the drill string system were analyzed based on MATLAB/Simulink. For the defined the drill string structure and system parameters, the critical value of stick-slip vibration exists. During the rotary speed increasing, drilling pressure decreasing and damping ratio rising to the critical value, the stick-slip vibration of the drill bit will disappear. The stick-slip vibration will be suppressed by the adding number of the blades.