钻铤连接螺纹断裂失效分析及结构优化

针对钻铤断裂事故，建立了2种普通API钻铤螺纹连接部位的有限元模型，并用有限元方法分析了不同模型在不同钻压条件下的应力分布情况，同时对API标准应力减轻槽的钻铤公头螺纹连接部位进行了结构优化。以公头螺纹连接处2个过渡圆角半径R1、R2为设计变量，分析了在一定条件下不同尺寸的R1、R2所对应的螺纹连接处应力的分布情况，改进的螺纹应力减轻槽可有效降低螺纹连接处的应力集中水平，并成功解决了库尔德地区钻铤螺纹断裂失效事故。

Failture Analysis of Drilling Collar Thread Connections and Structure Optimization

Thread connections failture is the main factor for the drilling collar broking,which accounted for a large proportion of downhole accidents about drilling tools,in fact,fatigue is the mian reason for thread failture.The finite element models for collar's thread connection part with 2 types of thread were created,the stress distribution was analyzed in different WOB using linear elasticity finite element method,thread of box connection parts were optimized in structure for collars using API standard stress r...