油气管道腐蚀与防护研究进展

随着管网的复杂化和管道腐蚀的多样化,管道老化问题日益显著,管道失效事故发生率上升,造成巨大的经济损失。分析了油管腐蚀的影响因素,管外土壤、管内输送介质及管杆腐蚀磨损是引起油管腐蚀的重要因素。归纳了油管腐蚀的一般特征,油管腐蚀是多种介质综合作用的结果,系统性总结了H_2S、CO_2腐蚀机理。H_2S腐蚀速率与其浓度呈正比关系,在浓度一定时,H_2S腐蚀速率主要取决于材料的硬度和强度。CO2腐蚀速率主要受温度、压力、介质流速以及pH值的影响。通过比较分析多种油管防护方法的优缺点,指出爆炸复合油管防护性能强且有效期长,是一种最适合油气井长效防护的方法。对管道施加外防护层和内壁检测是油管防护的有效手段,有益于降低油管事故率和提高油田综合效益。

Oil-Gas Pipe Corrosion and Protection

With the complexity of pipeline network and diversification of pipe corrosion, pipeline aging is increasingly serious. As a result, pipe failure accident rate keeps rising, and huge economic loss occurs as well. Based upon analysis of influencing factors of pipe corrosion, soil outside pipe, transmission medium inside pipe and corrosive wear between rods and pipes were verified to be important factors causing pipe corrosion failure. General characteristics of pipe corrosion were summarized, it was pointed out that pipe corrosion was a result of the combined action of multiple mediums. Corrosion mechanisms of H2S and CO2 were systematically summarized. Corrosion rate of H2S was proportional to its concentration. The corrosion rate of H2S mainly depended on hardness and strength of the material. While, the corrosion rate of CO2 was mainly affected by temperature, pressure, medium velocity and pH value. According to comparative analysis of advantages and disadvantages of different pipe protection methods, explosion composite tubing method was proposed to be a long-lasting protection method for oil-gas wells due to excellent protective properties and long term of validity. Besides, applying external protective coating to pipe and detecting inner wall were effective measures of pipe protection, which was conductive to reducing pipeline failure accident rate and thus improving comprehensive benefits of oilfield.