储气井螺纹连接安全性有限元模拟分析及实验研究

Experimental study and finite element simulation on safety performance of gas storage well's thread joint

储气井是一种新型压力容器,其螺纹连接的安全性目前既没有经过充分的研究论证,也没有经过实践的充分检验。通过实验和有限元模拟方法,对储气井螺纹连接的安全性进行了分析研究,得出了以下结论:(1)储气井模拟构件在极限内压实验过程中,在管体发生强度失效前,螺纹连接接头部位先发生泄漏失效,表明螺纹连接接头是储气井的薄弱环节;(2)储气井在极限内压条件下的破坏模式为"漏而不破",这一特性有益于保障储气井的安全;(3)螺纹沟槽对于井管管体而言是一种"损伤",但其并没有增高螺纹连接接头部位的结构应力,原因是因为接箍起到了加强作用;(4)螺纹连接接头部位螺纹牙底存在应力集中,可能会导致疲劳失效,建议设计时予以重点考虑,内压疲劳实验结果显示螺纹连接接头的抗疲劳性能满足储气井一般工况要求。

Gas storage well was a new type of pressure vessel.Safety performance of the gas storage well was neither studied well nor verified by practice.The current paper studied the gas storage well by experiment and finite element simulation.Safety performance of the thread joint was analyzed.The following conclusions were drawn：1） Utmost internal pressure experiments were made on gas storage well and leakage failure came forth at tread joints before the pipe burst,which revealed that the thread joint was the weakest part of the gas storage well;2） The breakage form ＂leakage but no burst＂of the gas storage well was displayed during the utmost internal pressure experiment,which was helpful for gas storage well＇s safety;3） It was found out that the structural stress was not increased for the thread groove＇s damage to the pipe and the reason was that the coupling strengthened the thread joint;4） Stress concentration was discovered at the joint thread,which would lead to fatigue failure that should be taken into account during engineering design of gas storage well.The cycling test of the gas storage well displayed that anti-fatigue of the thread joint fit the common working conditions of the gas storage well.