钻柱失效的动态断裂力学探讨

Discuss on Failure of Drill-string in Dynamic Fracture

石油钻井过程中,钻杆加厚过渡带刺穿和钻具螺纹断裂是最常见的钻柱失效形式,影响了钻井安全和经济效益,一直是国内外冶金和石油钻井研究的重点。传统的断裂力学只能解释石油管柱静态断裂问题,而不能解释动载下钻柱失效问题。文章采用动态断裂韧性评价钻杆断裂性能,在对现有动态断裂韧性测试方法进行研究的基础上,提出用动态断裂力学理论研究钻柱失效问题的理论及其测试方法。通过实验研究了国内外钻杆厂家的材料的动态断裂韧性,得出了钻杆材料动态断裂韧性与钻杆失效的相关性。

During oil drilling, the fracture of drill tool thread and piercing of upset drill pipe is a common form for drill string failure and therfore become an object of study for petroleum drilling and metallurgy at home and abroad. The classical fracture mechanic can only explain the static fracture problem of drill string, but it is incapble of explain drill string failure under dynamic load. Based on the present test method of dynamic fracture toughness, a way to study failure mechanism of drill string are propsoed. The dynamic fracture toughness of drill pipe material of manufacturer at home and abroad are investigated and the correlations between dynamic fracture toughness of drill pipe material and failure of drill pipe are obtained.