CO_2分压对J55油管腐蚀产物膜特征的影响  

Effect of CO_2 partial pressure on the characteristics of corrosion scale formed on J55 Tubing

作　　者：朱世东[1,2] 李金灵[3] 马海霞[2] 李建东[1] 张永强[1] 

机构地区：[1]延长石油(集团)有限责任公司研究院,陕西西安710075 [2]西北大学化工学院,陕西西安710069 [3]西安石油大学化学化工学院,陕西西安710065

出　　处：《西安石油大学学报（自然科学版）》2014年第2期94-98,103,共6页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：“863计划”资助项目“二氧化碳地质封存关键技术”(编号:2012AA050103);国家科技支撑计划项目“陕北煤化工CO2捕集、埋存与提高采收率技术示范”(编号:2012BAC26B00);西安石油大学博士科研启动项目(编号:2012BS001)

摘　　要：采用高温高压釜模拟井下动态腐蚀环境,使用扫描电镜(SEM)观测J55油管CO2腐蚀产物的结构特性,利用电化学技术研究腐蚀产物膜的电化学特征,使用X-射线衍射(XRD)分析腐蚀产物的成分。结果表明:随着CO2分压的升高,试样表面上的沉积物量和厚度逐渐增大,J55油管点蚀越发严重;膜层局部缺陷(如孔洞)是导致J55油管基体表面点蚀的主要诱因;在高CO2分压条件下,产物膜厚度增长变慢;随着CO2分压的升高,腐蚀产物膜保护性能降低,腐蚀产物膜的电位逐渐降低,电流密度逐渐增大,容抗弧半径逐渐减小,腐蚀受扩散控制减弱;高的CO2分压促进钙盐和镁盐的沉积,腐蚀产物不仅含有FeCO3和少量的Fe3C,还含有复盐Fe(Ca,Mg)(CO3)2。The downhole dynamic CO2corrosion environment of J55 tubing is simulated by high-temperature and high-pressure autoclave,the structural feature of the corrosion scales formed under different CO2partial pressure is observed by SEM,the electrochemical polarization curves and the impedance spectroscopies of the corrosion scales are obtained to study the electrochemical characteristics of the corrosion scales,and the composition of the corrosion scales are analyzed by XRD. The results show that: as CO2partial pressure increases,the amount and the thickness of the sedments on the surface of the samples increases,and the pitting corrosion of J55 tubing will become more serious; the local defects( such as holes) of the corrosion scales are responsible for the pitting corrosion of the metal substrate,and the growth rate of the thickness of the corrosion scales becomes slow at high CO2partial pressure; with the increasing of CO2partial pressure,the protective performance and the potential of the CO2corrosion scales are decreasing,decreases,the corrosion current density is increasing,the radius of capacitive reactance arc is decreasing,and the diffusion on the CO2corrosion is decreasing; high CO2partial pressure promotes the deposition of calcium salt and magnesium salt,and there are not only FeCO3and a little of Fe3C, but also double salt Fe( Ca,Mg)( CO3)2in the CO2corrosion scales at high CO2partial pressure.

关 键 词：J55油管 CO2腐蚀 腐蚀产物膜 点蚀 

分 类 号：TE988[石油与天然气工程—石油机械设备] TG172[金属学及工艺—金属表面处理]