摘要
氧腐蚀是限制注空气技术发展的重要因素之一,通过失重法以及XRD、EDS和SEM分析等方法,研究了注空气过程中井下管柱腐蚀规律及对应的防护措施。结果表明:氧腐蚀速率随着氧分压增大而加快,即使常压空气下腐蚀速率仍高于行业标准;存在一个临界温度及矿化度条件,使氧腐蚀速率达到最高;流体流度增大有利于加剧腐蚀;腐蚀产物膜主要成分包括γ-FeO(OH)、β-FeO(OH)、Fe_3O_4、α-FeO(OH)等,结构疏松不致密,对钢体保护作用不大。可见有效控制氧腐蚀需考虑多种防腐措施,包括优选管材、利用润滑油脂对钢材表面进行处理、pH调整、加注缓蚀剂等。
Severe oxygen corrosion is one of the key factors that limit the advance of the air injection technology for EOR in the oil field.Methods of weight loss,XRD analysis,EDS analysis and SEM analysis were used to clarify the corrosion law and protective measures of downhole string in air injection process.The experimental results indicate that oxygen corrosion rate increases with rising pressure,even at the atmospheric condition steels also suffer severe corrosion with the rate much larger than the industrial standard(0.076mm/a).There exist a critical temperature and a critical salinity at which the oxygen corrosion rate can reach the largest.In addition,increasing fluid flow rate is also conducive to oxygen corrosion.The main elements of corrosion products areγ-FeO(OH),β-FeO(OH),Fe3O4andα-FeO(OH).The structure of corrosion film is loose,therefore has little protective effect on steel matrix.The validity of the anti-oxygen corrosion measures has been verified.Various anti-corrosion measures should be considered to effectively control the oxygen corrosion of downhole string,including selecting high-quality steel type,the use of grease to treat the steel surface,pH adjustment,and filling or injecting corrosion inhibitor.
作者
李晓东
LI Xiao-dong(Research Institute of Oil Production Engineering Technology, Zhongyuan Oilfield Company SINOPEC, Puyang 457001,China)
出处
《科学技术与工程》
北大核心
2018年第35期18-25,共8页
Science Technology and Engineering
基金
国家科技重大专项(2016ZX05017-003)资助
关键词
注空气
氧腐蚀
影响因素
腐蚀产物
防腐措施
air injection
oxygen corrosion
influential factor
corrosion product
prevention measure
