小井眼钻柱瞬态动力学研究及应用

考虑小井眼细长钻柱沿井深和井眼圆周方向的随机接触碰撞，建立了钻柱瞬态动力学模型。运用动力间隙元不仅能合理描述钻柱与井壁的接触碰撞过程，还能考虑井壁变形和泥饼的能量吸收，并用Newmark法求解钻柱动力学平衡方程。通过钻井全尺寸模型装置上的钻柱动力学试验，对理论计算结果进行了验证，也为钻头干扰力确定提供了依据。经大庆油田14口小井眼井应用表明，由钻柱动力学分析所设计的钻柱结构没有发生井下断钻具事故，防斜性能也比较好，机械钻速得到明显提高。

THE DYNAMIC ANALYSIS AND APPLICATION OF DRILLING STRING IN SLIM HOLE WELL

By analyzing the random contact and impact between drilling string and bore hole wall at arbitrary depth and circle direction in slim hole well, a dynamic model of whole drilling string is presented. This model is solved by dynamics gap element which can not only describe the contact and impact between drilling string and bore hole wall but also present the deformation of bore holewall and energy absorption of mud cake. The dynamic equilibrium equation is solved by Newmark method. Through laboratory test of drilling string dynamics at the normal size simulating drilling device, the theoretical results are verified and the interference force of bit is determined. The field tests in 14 slim hole wells in Daqing Oil Field show that no fatigue failure in the drilling string to be designed by dynamics analysis can be developed, and the better defense inclination is obtained with drilling speed being increased significantly.