考虑运动状态时全井段钻柱疲劳裂纹扩展寿命计算研究  

Research on How to Predict the Drillstring Fatigue Life of Whole Well with Precession and Backward Precession

作　　者：林元华[1] 邹波[1] 付建红[1] 施太和[1] 董伟[2] 李润方[3] 

机构地区：[1]西南石油学院油气藏地质及开发工程国家重点实验室,成都610500 [2]四川石油管理局川西北矿区,江油621700 [3]重庆大学机械传动国家重点实验室,重庆400044

出　　处：《机械科学与技术》2005年第4期404-407,共4页Mechanical Science and Technology for Aerospace Engineering

基　　金：国家自然科学基金项目 ( 59804009 );中国石油天然气集团公司"九五"应用基础研究项目"钻柱动力学研究与现场应用"(970409-01)资助

摘　　要：旋转钻进中钻柱既自转又反转,当其通过弯曲段或大间歇环空段时,偏心反转引起较大的弯曲应力,在复合载荷作用下常造成钻柱疲劳损伤。因此,钻柱疲劳寿命预测对钻柱的合理使用及损伤评估有重要价值。本文以全井段钻柱为研究对象,考虑了其进动与反进动状态,通过摩阻/扭矩分析确定了其轴向载荷及扭矩,并运用动力学观点分析了钻柱在不同井眼环空下的弯曲应力,由此计算出了全井段钻柱的合成应力,并结合Paris公式得出了钻柱疲劳寿命的计算方法。最后,编写了计算全井段钻柱受力和疲劳裂纹扩展寿命的计算机软件。算例表明,该方法能客观地反映井身结构、钻具组合及钻柱运动状态对钻柱疲劳裂纹扩展寿命的影响。Drillstring rotates clockwise and counter-clockwise during drilling. When it rotates in the bending section or section which has large free annular space, large alterative bending stress generated from load and eccentric reversal will give rise to the fatigue failure of drillstring. So predicting drillstring′s fatigue life is helpful to drillstring′s use and damage inspection. In this paper, the drillstring of the whole well is studied, with the moving state of the drillstring considered. The axial load and torque was obtained by torque/drag model of drillstring. Furthermore, the bending stress of drillstring in different annular space section was also computed. Hence, the fatigue life of whole-well drillstring was predicted based on the stress analysis and Paris formula. Finally, the software for calculating whole-well drillstring′s stress and propagation life of crack was compiled. Examples indicate that this method can reflect the effect of the casing program, BHA(Bottom hole assembly) and precession on the drillpipe′s fatigue life.

关 键 词：钻柱 反进动 摩阻/扭矩 井身结构 钻具组合 疲劳寿命 

分 类 号：TD26[矿业工程—矿井建设]