两种油管钢在模拟油田高温高压O_(2)-CO_(2)地层水环境中的腐蚀行为

Corrosion Behavior of Two Kinds of Tubing Steels in Simulated High Temperature and High Pressure O_(2)-CO_(2) Formation Water Environment of Oil Field

氧气与二氧化碳共存环境的腐蚀已成为油田注入井况中金属材料损伤的主要诱因。采用高温高压釜模拟了西部某油田注入井工况(O_(2)-CO_(2)共存环境),通过腐蚀失重试验、点蚀三维形貌分析、腐蚀产物显微分析等方法研究了P110和3Cr两种油管钢在高温高压、O_(2)-CO_(2)共存的高矿化度地层水环境中的腐蚀行为。结果表明:两种油管钢在O_(2)-CO_(2)共存环境中遭受了严重的均匀腐蚀和局部腐蚀;在90~150℃内,两种材料的腐蚀随温度升高而加剧,均匀腐蚀速率增幅达79.7%,最大点蚀速率的增幅达143.4%;O_(2)与CO_(2)共存时,阴极反应显著加快,加速了保护性较差的铁氧化物的形成,导致严重的均匀腐蚀和局部腐蚀,而低Cr钢中的Cr不足以改善腐蚀产物膜的保护性,使该钢不能适应O_(2)-CO_(2)共存环境。

The corrosion caused by the coexistence of oxygen and carbon dioxide has become the main cause of metal material damage in oilfield injection well conditions.The corrosion behavior of P110 and 3Cr oil pipe steels in a high salinity reservoir water environment with high temperature,high pressure,and O_(2)-CO_(2) coexistence was studied by simulating the injection well operating conditions(O_(2)-CO_(2) coexistence environment)in a western oilfield using a high temperature and high presure reactor.Corrosion weight loss testing,three-dimensional morphology analysis of pitting corrosion,and microscopic analysis of corrosion products were also conducted.The results show that the two types of oil pipe steels suffered severe uniform corrosion and localized corrosion in an environment where O_(2) and CO_(2) coexisted.Within the temperature range of 90-150°C,the corrosion of the two materials intensified with increasing temperature,with a uniform corrosion rate increase of 79.7%and a maximum pitting corrosion rate increase of 143.4%.When O_(2) and CO_(2) coexisted,the cathodic reaction significantly accelerated,accelerating the formation of poorly protected iron oxides,leading to severe uniform corrosion and localized corrosion.However,the content of Cr in low Cr steel was not sufficient to improve the protection of the corrosion product film.So the low Cr steel could not adapt to the environment where O_(2) and CO_(2) coexisted.