牙轮钻头横向振动动力学仿真模型

为探寻在实际钻井过程中钻头的运动轨迹和与井壁碰撞时撞击力的变化规律，利用有限元方法，建立钻柱横向振动的有限元动力学模型，并在考虑钻头－岩石互作用力学模型的基础上，建立了钻头横向振动动力学仿真模型，通过实验及相关数据得到预测钻头与井壁碰撞时撞击力大小的计算公式。根据所建模型及仿真过程，编制了牙轮钻头横向振动的仿真程序。对８ＸＨＰ２Ｓ钻头的仿真结果表明，钻头与井壁的最大碰撞力可达１５７ｋＮ，这对于钻头的运动规律及工作性能均有影响，是造成钻头破坏的一个可能的原因。

Dynamic simulation model for lateral vibration of cone bits

By means of numerical solution method, drillstring's finite element models, and based on mechanical models of bit/rock interaction, the dynamic models for lateral vibration of a cone bit are established. The contact models of bit/wellbore interaction are created on the basis of the experimental data. According to the models and the simulating processing, the simulation programme for the lateral vibration of the cone bit is developed. An example of simulation shows that the maximum value of the bit/wellbore impact force can reach 157kN, which has influence on the motion pattern and performance of the bit to a certain degree, and may cause the failure of the bit.