摘要
结合断裂力学理论，通过慢应变拉伸等系列实验，探讨了拉应力加速油气井套管腐蚀的机理，认为腐蚀和碰伤会加快套管裂纹的孕育，断裂韧性和断裂强度因子的变化对裂纹的扩展起加速作用。慢应变拉伸实验结果表明，拉应力作用下，钢材在强腐蚀性地层水中的力学性能比空气中明显下降，而添加缓蚀剂后，力学性能得到改善；断口电镜扫描显示在地层水中断口的裂纹增多，同时断裂敏感参数也说明钢材在地层水中出现了应力腐蚀断裂特征；试样失重实验结果证明应力腐蚀速率比无拉应力时高出13.6％～24％，添加缓蚀剂可使应力腐蚀速率显著降低；能谱分析表明缓蚀剂通过迅速成膜减缓腐蚀对裂纹的扩展作用，较大幅度减缓了钢材的应力腐蚀速率，同时可以使钢材的力学性能的受损幅度降低。
The mechanism that corrosion rate of casing in oil or gas well is accelerated by tensile stress was studied by series experiments combined with fracture mechanics theory. Process of fracture origination will be shortened by corrosion and dog marks,and fracture extension will be accelerated due to change of fracture toughness and intensity factor. Experimental results show that stress corrosion cracking characteristics occurred on fractured steel samples with tensile stress which were put inside strong corrosive formation water,and corrosion rate is about 13.6%-24% more than the rate of the other samples without tensile stress. Corrosion inhibitor can quickly form a film to shield from steel and decelerate fracture speed,and reduce the corrosion rate of steel sample and reduce the weakening extent of steel sample.
出处
《钻采工艺》
CAS
北大核心
2007年第1期84-86,共3页
Drilling & Production Technology
基金
国家自然科学基金(No.50174047)
上海市重点学科建设项目(No.Y0103)。
关键词
拉应力
断裂力学
应力腐蚀机理
套管
缓蚀剂
tensile stress, fracture mechanics, stress corrosion mechanism, casing, corrosion inhibitor
作者简介
顾春元（1970-），博士研究生，1993年毕业于西安石油大学，长期从事油气田开发工程技术研究、方案设计和现场生产服务。地址：（200072）上海市延长路149号，电话：（021）56333256，E—mail：wein1989@163.com
