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利用钻柱纵向振动数学模型,在钻头处分别施加激励位移(即激励位移法)和激励力(即激励力法),对比分析了减振器刚度和安装位置对常用塔式钻柱钻杆中最大轴向应力振幅和井口钻柱轴向位移振幅的影响。分析发现:二者随转速的变化曲线呈连续的凹坑形,钻井时应优选转速使二者尽可能小;减振器的安装位置和刚度对二者有重要影响,当钻头处采用不同的激振条件(激励位移法和激励力法)时,减振器对二者的影响规律不同,甚至相反。应该采用激励位移法研究钻柱纵向振动问题。今后应考虑减振器阻尼的影响,通过井下实测评价减振器的作用和开发新型减振器。
Using the longitudinal vibration mathematical model of the drill string, the excitation displacement (ie excitation displacement method) and the excitation force (ie the excitation force method) are respectively applied to the drill bit. The stiffness and installation position of the shock absorber are compared and analyzed. The maximum axial stress amplitude and the axial displacement amplitude of the well head. It is found that the curves of the two curves are continuous concave dimples with the rotation speed, and the rotation speed should be optimized so that the two are as small as possible. The mounting position and rigidity of the shock absorber have an important influence on both of them. Excitation conditions (excitation displacement method and excitation force method), the shock absorber on the impact of the two different laws, and even the opposite. Excitation displacement method should be used to study the longitudinal vibration of drill string. In the future, the influence of shock absorber damping should be considered, the effect of shock absorber measured through underground and the development of new shock absorber.