L80油管钢实际腐蚀状况评估及室内电化学和应力腐蚀研究  

Evaluation of Actual Corrosion Status of L80 Tubing Steel and Subsequent Electrochemical and SCC Investigation in Lab

作　　者：李清[1,2] 张德平 王薇 吴伟 卢琳 艾池[1] LI Qing;ZHANG Deping;WANG Wei;WU Wei;LU Lin;AI Chi(School of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,China;Carbon Dioxide Development Company,Jilin Oilfield Branch of Petrochina,Songyua 138000,China;Research Institute of Oil&Gas Engineering,Jilin Oilfield Branch of Petrochina,Songyuan 138000,China;Corrosion and Protection Center,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]东北石油大学石油工程学院,大庆163318 [2]中国石油吉林油田分公司二氧化碳开发公司,松原138000 [3]中国石油吉林油田分公司油气工程研究院,松原138000 [4]北京科技大学腐蚀与防护中心,北京100083

出　　处：《中国腐蚀与防护学报》2020年第4期317-324,共8页Journal of Chinese Society For Corrosion and Protection

基　　金：国家重点研发计划(2018YFB0605502)。

摘　　要：重点关注了吉林油田中更换的L80油套管的腐蚀行为,通过SEM和体式显微镜对其表面形貌和腐蚀产物进行了分析,同时采用电化学测试和慢应变速率拉伸实验对模拟油井采出液环境中试样的电化学性能和应力腐蚀开裂风险进行了评估。结果表明,在吉林油田服役一段时间后,L80套管钢的外壁腐蚀比较轻微,主要以均匀腐蚀为主,仅有少量的腐蚀产物在表面附着;而L80套管的内壁腐蚀程度相对严重,有一层致密的腐蚀产物覆盖在基体表面,且在产物膜下出现了一定程度的局部腐蚀和点蚀坑,伴随着一些细小的微裂纹。室内研究表明,服役环境中的水分增加、CO2和H2S的产生均能加速其电化学过程,从而加速L80钢在油田采出液中的腐蚀。然而,这些因素对其应力腐蚀敏感性影响较小。L80钢在模拟油田采出水环境中具有较好的耐应力腐蚀开裂性能,说明其作为油井中的油套管材料具有较小的应力腐蚀开裂风险。The work aims to evaluate the risk of corrosion and stress corrosion cracking(SCC)of L80 tubing steel during long-term service in Jilin Oilfield.The surface morphology and corrosion products of L80 tubing steel replaced from Jilin Oilfield were analyzed by SEM and laser confocal microscope.Besides,the electrochemical means and slow strain rate tensile tests were used to evaluate the electrochemical behavior and SCC risk of L80 tubing steel in a simulated oil well production fluid.Results indicated that,after serving for several years,the degree of corrosion on the outer wall of L80 tubing steel was mild and dominated by uniform corrosion accompanied with few corrosion products.In the contrast,the inner wall of the L80 tubing steel was badly corroded with a scale of dense corrosion products,beneath which there existed certain localized corrosion,deep pits,as well as microcracks.The indoor tests indicated that the increase in water content,CO2 and H2S accelerated the electrochemical corrosion process,thereby promoting the corrosion in the oilfield produced water,while these factors affected little on the SCC sensitivity.In sum,L80 steel displayed good resistance to SCC in the simulated oilfield produced water environment,implying very low risk of SCC for L80 steel as casing materials for oil well.

关 键 词：L80油套管 CO2/H2S 含水率 应力腐蚀 点蚀 

分 类 号：TG172[金属学及工艺—金属表面处理]