集输管道内腐蚀原因分析及对策研究

在石油石化行业,腐蚀是危害管道安全、引起管道失效的重要因素。统计数据表明:腐蚀相关的事故占总体事故比例在25%以上。通过对某区块采出液成分进行分析,发现腐蚀形态以局部点蚀为主,腐蚀机理主要是垢下浓差腐蚀和细菌腐蚀,腐蚀的主要介质是H2S、CO2、SRB,水中的Cl-作为催化剂对腐蚀起到自加速的作用,随后通过添加缓蚀剂、旋转气流法管道内涂层和非开挖内衬修复技术对腐蚀管道进行防护与修复,其中旋转气流法适用于新建或未发生过腐蚀穿孔的管段,PCE内衬修复技术适用于腐蚀较为严重的管段,目前3种防护措施都取得了良好的应用效果,可实现隔离腐蚀介质、延长管道寿命的目的,研究结果可供其他油气田和管道行业借鉴。

CAUSE ANALYSIS AND COUNTERMEASURE RESEARCH OF CORROSION IN GATHERING PIPELINE

In the petroleum and petrochemical industry, corrosion is an important factor that endangers pipeline safety and causes pipeline failure. According to statistical data, corrosion-related accidents account for more than 25% of the total accidents. By analyzing the composition of the produced fluid in a certain block, it is found that the corrosion form is mainly local pitting;the corrosion mechanism is mainly under-scaling concentration corrosion and bacterial corrosion;the main corrosion medium is H2S, CO2 and SRB;and Cl- in water has a self-accelerating effect on corrosion as a catalyst. Then, the corroded pipelines were protected and repaired by adding corrosion inhibitors, adopting swirling flow method for pipeline undercoating and trenchless lining repair technology. The swirling flow method is suitable for new pipeline sections or sections without corrosion perforation. PCE lining repair technology is suitable for more severely corroded pipeline sections. At present, the three protective measures have obtained good application effects. The goal of isolating corrosive media and extending the service life of the pipelines can be achieved. The research results can provide reference for other oil and gas fields and pipeline industries.