Method of Equilibrium Differential Equation for Analysis of Strength of Large Deflection Drill String
-
摘要: 对小井眼、大曲率井中钻柱强度问题,以井轴为基准轴,在对井轴弯挠描述和钻柱微段三维受力变形分析的基础上,建立大位移钻柱平衡微分方程,采用Longe-Kutta法解之求内力,并依此求应力和建立强度条件.对H767侧钻水平井施工中钻柱应力计算分析,结果说明与有限元模型和弹性化软绳模型比较相吻合,该模型比有限元模型计算简捷方便;比弹性化软绳模型更完善可信;该井钻柱破坏事故愿因在于井眼曲率过大,兼有应力集中.Abstract: To counter the strength problem of drill string in well of large curvature and small diameter,well axis was taken as datum axis.Based on description of deflection of well axis and on analysis of three dimensional forces of a small section of drill string,equilibrium differential equations of large deflection drill string were established.The internal forces were found by Longe-Kutta method.The stresses were found by using them and the strength prerequisite was established.Stresses of drill string in lateral horizontal well H767 were computed.The results are in agreement with those of finite element model and soft-rope rigidified model.But the method is simpler for computation than finite element model and is more perfect than soft-rope rigidified model.Curvature of the well is too large and there is stress concentration so that the fraction accident of drill string occurs.
-
Key words:
- lateral horizontal well /
- large deflection /
- drill string /
- stress /
- strength /
- equilibrium differential equation
-
[1] 刘延强,吕英民.环空钻柱结构三维非线性分析[J].应用数学和力学,1994,15(3):259-272. [2] LIU Yan-qiang.Strength Analysis of three-dimensional large deflection drill string in annulus[A].In:CHIEN Wei-zang Ed.Proceeding of 3rd International Conference on Nonlinear Mechanics[C].Shanghai:Shanghai University Press,1998,8:301-304. [3] 刘延强.大挠度钻柱强度分析和简化方法[A].见:杜庆华编.力学与应力工程[C].北京:中国林 业出版社,1998,413-416. [4] 刘延强,蔡强康,吕英民.三维井眼轴线的数值模拟计算[J].石油大学学报,1990,14(3):45-54. -
点击查看大图
计量
- 文章访问数: 2446
- HTML全文浏览量: 74
- PDF下载量: 628
- 被引次数: 0
下载:
