某水平井钻杆管体断裂失效机理分析  

Failure analysis of drill pipe body fracture in a horizontal well

作　　者：余世杰[1,2] 林元华[1] 陈猛[2] 欧阳志英[2] Yu Shiji;Lin Yuanhua;Chen Meng;Ouyang Zhiying(School of Materials Science and Engineering, Southwest Petroleum University, Chengdu Sichuan 610500 ,China;Shanghai Hilong Oil Tubular Goods Research Institute, Shanghai 200949,China)

机构地区：[1]西南石油大学材料科学与工程学院,四川成都610500 [2]上海海隆石油管材研究所,上海200949

出　　处：《金属热处理》2019年第3期212-218,共7页Heat Treatment of Metals

基　　金：上海市产学研合作项目(CXY-2011-13)

摘　　要：某水平井在倒划眼起钻过程中频繁发生憋钻现象,解卡过程中位于下部水平段的一钻杆本体处断裂。对断裂钻杆进行了力学性能、显微组织及有限元受力模拟等分析。结果表明,该钻杆在通过硬质岩层时,外壁与井壁发生了严重的摩擦磨损现象,使得钻杆外壁温度急剧升高,加之钻井液的冷却作用,外壁表层发生了二次马氏体相变,产生了硬化层,在井下复合载荷的作用下,在钻杆加厚过渡带应力集中区域的硬化层萌生早期疲劳热裂纹,并最终穿透整个钻杆壁厚导致断裂失效。通过此次疲劳热裂纹失效机理分析,提出了对钻杆外壁采用防磨装置,降低钻杆表面由于摩擦磨损作用产生的热能等改善措施。In the process of pouring eye drilling,a horizontal well often occurs,a drill pipe body located in the lower horizontal section broke in the process of unloading. The fractured drill pipe was analyzed by means of mechanical property,microstructure and drill pipe force simulation analysis. The results show that when the drill pipe passes through the hard rock layer,the external surface of the pipe has serious friction and wearing with the well wall,which makes the temperature of the outer wall of the drill pipe rise sharply,combined with the cooling effect of the drilling fluid,twice martensite transformation occur on the surface of the outer wall,resulting in a hardened layer,under the action of downhole composite load,The hardened layer at the thickened transition zone of the stress concentration area of the drill pipe sprouts the fatigue microcracks,and finally penetrates the whole drill pipe wall thickness,resulting in fracture failure. Through the analysis of the failure mechanism of fatigue thermal crack,the improvement measures such as anti-wear device for the outer wall of drill-pipe and reducing heat energy caused by friction and wear on the drill pipe surface are put forward.

关 键 词：断裂失效 摩擦磨损 热疲劳裂纹 淬火硬化层 水平井 

分 类 号：TG161[金属学及工艺—热处理]