多轴交变载荷下套管长圆螺纹疲劳失效分析及寿命预测  

Fatigue Failure Analysis and Fatigue Life Prediction of the Long Round Thread of the Casing Under Multi-axial Alternate Load

作　　者：谢士远 赵朝阳 关志刚[1] 王宏峰 宋琳 林铁军[2] 张强[2] Xie Shiyuan;Zhao Chaoyang;Guan Zhigang;Wang Hongfeng;Song Lin;Lin Tiejun;Zhang Qiang(PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang 834000,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploration,Southwest Petroleum University,Chengdu,Sichuan 610500,China;PetroChina Yumen Oilfield Company,Jiuquan,Gansu 735000,China)

机构地区：[1]中国石油新疆油田分公司,新疆克拉玛依834000 [2]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [3]中国石油玉门油田分公司,甘肃酒泉735000

出　　处：《特种油气藏》2021年第3期168-174,共7页Special Oil & Gas Reservoirs

基　　金：国家自然科学基金“极端条件下气井管柱耦联振动力学行为与控制基础理论研究”(51974271);中国石油重大工程技术现场试验项目“准噶尔南缘和玛湖等重点地区优快钻完井技术集成与试验”(2019F-33)。

摘　　要：在下套管以及压裂作业过程中,套管螺纹在多轴交变载荷作用下极易发生疲劳失效,影响施工进度。针对该问题,通过有限元方法,利用Abaqus软件建立套管长圆螺纹有限元模型,对上扣后套管螺纹在拉伸、压缩、内压力等多轴交变载荷作用下的应力、应变进行了分析,并基于Mises屈服准则的寿命评估法对套管螺纹在多轴交变载荷下的寿命进行计算。研究表明;在拉伸、压缩、内压力等多轴交变载荷作用下,套管螺纹上最大应力都出现在公扣大端5扣齿底处;在轴向拉伸、压缩交变载荷作用下螺纹疲劳寿命仅为1298次,内压力为46、66、100 MPa时,螺纹疲劳寿命随内压力增加呈现递减趋势,分别为1094、1050、901次。该研究结果对致密油等非常规油田在压裂过程中套管螺纹失效分析具有参考意义。During casing running and fracturing,it is easy to cause fatigue failure to casing threads under multi-axial alternate loads,affecting the construction progress.To address this problem,a finite element model of long round thread of the casing was established by Abaqus software with finite element method,and an analysis was conducted on the stresses and strains of casing thread under multi-axial alternate loads such as tension,compression,and internal pressure after buckling,and the life of casing threads under multi-axial alternate load was calculated by the life assessment method based on the Mises yield criterion.It was found in the study that under the action of multi-axial alternate loads such as tension,compression,and internal pressure,the maximum stress on the casing thread acted at the bottom of the 5 teeth at the big end of the male buckle;under the action of alternate loads such as axial tension and compression,the fatigue life of the lower thread is only 1298 times.When the internal pressure was 46,66,and 100 MPa,the fatigue life of the thread was decreased with the increase of the internal pressure,1094,1050,and 901 times,respectively.The study results provide a reference for the analysis of casing thread failure during fracturing in tight oil and unconventional oilfields.

关 键 词：套管螺纹 应力 应变 多轴交变载荷 塑性变形 疲劳寿命 

分 类 号：TE256[石油与天然气工程—油气井工程]