中文摘要：

针对钻柱振动引起的钻具失效问题,综合考虑钻柱弹性变形及钻柱与井筒的碰撞摩擦相互作用,研究了钻头与下部钻柱的振动特性。根据哈密顿原理和有限单元法,建立了全井钻柱纵、横、扭耦合振动动力学模型;将钻头、钻柱、井筒视为一个完整的系统,以川渝地区某中深井实钻操作参数、下部钻具组合（BHA）和井筒参数作为基本输入数据,采用非线性仿真技术,研究了不同井段钻柱以及钻头的振动规律,分析了钻头处的动态钻压、扭矩及转速波动情况。结果表明,钻头处振动剧烈,跳动幅度较大,因此有必要研究振动控制工具和方法,以减少振动对钻头的伤害,改善钻头的工作环境并提高钻进效率。形成的钻头-钻柱-井筒系统非线性仿真技术,为下部钻具组合优化、钻井操作参数优选、钻具失效预防乃至钻头优化设计,提供了可行的分析手段,为研究振动控制策略提供了基础技术支持。

英文摘要：

According to the drilling tools failure caused by the drill string vibration,the elastic deformation of drill string and interactions of collision and friction between drill string and borehole are considered comprehensively.The dynamic characteristics of drill bit and bottom hole assembly（BHA） are analyzed.A mechanics model considering the coupling of lateral vibration,longitudinal vibration and torsional vibration is established based on the Hamilton principle and the finite element method.Vibration laws of bit and drill string of different sections are analyzed by nonlinear simulation technology,especially the fluctuations of dynamic weight on bit（WOB）,torque and rotate speed.During the simulation,the bit,drill string and the borehole is taken as a whole system,and the basic input data such as operating parameters,BHA and borehole parameters of the model are real drilling parameters of certain mid-deep wells in Chuanyu region.The results show that vibration and bouncing are severe by a big margin at the drill bit.It is necessary to study the vibration control tools and methods for reducing the vibration damage of the drill bit and improving the working environment of drill bit and increasing drilling efficiency.The nonlinear simulation technology of bit-drill string-borehole system provides a feasible approach for optimizing the BHA and drilling parameters,preventing failures of the drilling tools and optimal design of the bit.It provids a foundational technical support for the vibration control strategy research.