深部地质钻探孔内钻杆动力响应特性研究

Research of dynamic response characteristics in the deep geological drilling hole

深部地质钻探时,钻杆受力条件复杂,振动形式多变且剧烈。为认识钻杆的动力学特征,减少钻杆失效风险,提高钻进效率,建立了仅考虑纵向振动和扭转振动耦合作用下的深部地质钻杆动力学分析模型,并推导了钻杆固有振动频率公式,在此基础上,借助ANSYS软件进行仿真分析。研究成果表明:在纵向(扭转)振动下,随着模态阶数的增加,钻杆的轴向(角)位移变化越来越复杂;随着模态阶数的增加,钻杆的固有频率呈现线性增加;在相同模态阶数条件下,随着深度的增加,固有频率逐渐降低,但其降幅逐渐减小;当激振频率与钻柱纵向(扭转)振动固有频率相近时,钻杆的轴向(角)位移达到极值。

In the deep geological drilling hole,the force condition of the drilling rod is complex,and the vibration form is changeable and intense.In order to understand the dynamic characteristics of drilling rod,and to reduce the risk and to improve the drilling efficiency,with the help of ANSYS software,this paper establishes a dynamic analysis model of deep geological drilling rod with the consideration of the coupling effect of longitudinal and torsional vibration.The natural vibration frequency formula of the drilling rod is inferred.The research result shows that under longitudinal(torsional)vibration,as the modal order increases,the axial(angular)displacement of the drilling rod becomes more and more complicated.With the increase of the drilling footage,the natural frequency of the drilling rod presents a linear increase.Under the same modal order condition,as the drilling depth increases,the natural frequency gradually decreases,but the amplitude gradually decreases.When the excitation frequency is close to the natural frequency of longitudinal(torsional)vibration of the drilling rod,the axis(angular)displacement of the drilling rod reaches the extreme value.