基于应力比的延长抽油杆疲劳寿命设计方法  

Design method for extending the fatigue life of sucker rod based on stress ratio

作　　者：王治磊 WANG Zhilei(Sinopec North China Oil and Gas Branch Oil Production Plant No.1,Shaanxi Xianyang 712000,China)

机构地区：[1]中石化华北油气分公司采油一厂,陕西咸阳712000

出　　处：《非常规油气》2023年第3期127-134,142,共9页Unconventional Oil & Gas

基　　金：国家科技重大专项“低丰度致密低渗油气藏开发关键技术”(2016ZX05048)。

摘　　要：有杆泵采油是目前各油田最常用的采油方式。为研究交变载荷对油井下部抽油杆柱疲劳寿命的影响,模拟抽油杆真实受力环境,开展了不同应力比条件下抽油杆疲劳性能试验。结果表明:1)抽油杆循环拉伸次数随抽油杆应力比增大而增大,当应力比大于0.45时趋于不变,抽油杆寿命与应力比关系进行曲线拟合,具有一元三次方程关系;2)生产井因工作条件不同,最下一级抽油杆柱应力比不同,实测应力比为0.19~0.51,平均值为0.30;3)生产井最下一级抽油杆疲劳寿命拐点应力比为0.37,推荐抽油杆抗疲劳设计应力比大于等于0.37;4)抽油杆柱底端采用加重抽油杆或加粗抽油杆可以提高最下一级抽油杆应力比。该设计方法对于延长抽油杆疲劳寿命具有实际指导意义。Rod pump oil production is currently the most commonly used oil production method in various oil fields.In order to study the influence of alternating load on the fatigue life of the pumping rod in the lower part of the well,the real stress environment of the sucker rod is simulated,and the fatigue performance test of the sucker rod under different stress ratio conditions is carried out.The results show that:1)The number of cycle stretches of the sucker rod increases with the increase of the stress ratio of the sucker rod,and when the stress ratio is greater than 0.45,the relationship between the sucker rod life and the stress ratio is curve fitted,with a unary cubic equation relationship;2)Due to different working conditions in the production well,the stress ratio of the lowest stage sucker rod column is different,and the measured stress ratio is 0.19~0.51,with the average value is 0.30;3)The inflection point stress ratio of the fatigue life of the lowest stage sucker rod in the production well is 0.37,and recommend that the strain ratio of the suction rod anti-fatigue design is greater than or equal to 0.37;4)The bottom end of the sucker rod column is weighted or thickened to increase the stress ratio of the lowest stage of the sucker rod.This design method has practical guiding significance for extending the fatigue service life of the sucker rod.

关 键 词：有杆泵采油 抽油杆疲劳寿命 疲劳性能试验 实测载荷 应力比设计 

分 类 号：TE35[石油与天然气工程—油气田开发工程]