【作者】 张海宝；

【导师】 刘猛； 刘永红；

【作者基本信息】 中国石油大学 ， 机械设计及理论， 2008， 硕士

【摘要】 CO₂驱油增产技术的广泛应用以及一些油气田采出液中本身所含有的CO₂,使得CO₂腐蚀成为困扰油气生产的一个主要问题。油气生产和运输使用的管线钢遭受CO₂腐蚀后,力学性能降低,使用寿命缩短,特别在设备发生CO₂局部腐蚀后,产生凹坑甚至穿孔,破坏更为严重。因此,研究CO₂腐蚀机理、腐蚀速率预测模型,分析设备遭受CO₂腐蚀后失效和破坏的原因,具有重要的工程应用价值。本文从腐蚀电化学着手,将油气田CO₂腐蚀进程分为三个阶段,指出扩散层传质过程是整个均匀腐蚀进程的速度控制步骤,在此基础上,利用极限扩散电流,推导出均匀腐蚀预测模型,并分析了影响CO₂均匀腐蚀的主要因素;CO₂腐蚀产物膜与腐蚀进程密切相关,总结国内外CO₂腐蚀产物膜的研究成果,分析研究得出腐蚀产物膜的形成过程;腐蚀产物膜破坏是发生局部腐蚀的诱导原因,但不同的局部腐蚀类型,具有不同的动力增长机理:点蚀可看做较低pH值下的均匀腐蚀,而流动诱导腐蚀和台面腐蚀受电极反应的放电步骤控制;推导出局部腐蚀速率预测模型,为油气田实际应用提供参考;油管发生CO₂局部腐蚀后,腐蚀穿孔失效,甚至在交变载荷作用下疲劳破坏,发生掉井;套管发生CO₂局部腐蚀后,在外压或内外压作用下,腐蚀凹坑处应力集中,达到屈服极限,发生破坏。更多还原

【Abstract】 With wide application of carbon dioxide injection technology to improve oil recovery and the produced liquid of some oil-gas field contains carbon dioxide, carbon dioxide corrosion become a main problem of oil-gas production. Mechanical properties and service-span of Pipeline equipment for oil-gas production and transportation decrease, especial localized corroded equipment are more likely to be damaged. So, it is very important to research the mechanism of carbon dioxide corrosion, the corrosion rate prediction model and analyze corrosion failure of the equipment.This thesis analyzes carbon dioxide corrosion using corrosion electrochemistry method and divide corrosion process into three steps, state that transmission process in diffusion layer control the whole general corrosion, deduct general corrosion rate prediction model, analyze the main factors which influence carbon dioxide corrosion; Corrosion product film is associate with corrosion process, after summing up research results of corrosion produce film home and abroad, analyze the corrosion product film forming process; The damage of corrosion product film induce localized corrosion and different localized corrosion style has different drive mechanism; Pitting corrosion can be considered to be general corrosion in low pH condition, flow induced corrosion and mesa type corrosion are controlled by the rate of electrode reaction; Deduct a localized corrosion rate prediction model which is useful for oil-gas field; Localized corroded tube are fatigue failure under alternating loads; Corroded casing damage when stress concentration excel yield limit at corrosion pit under external pressure or external and internal pressure.更多还原