L245M钢在油气田模拟水中的腐蚀行为研究

发布时间：2018-03-09 20:01

  本文选题：温度　切入点：醋酸浓度　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于油气田所处的环境十分复杂,在其开采和生产运输中,环境中大量的腐蚀介质会对石油工程采集输送管材造成很严重的腐蚀,严重影响工业生产进程,给社会经济带来巨额的损失同时破坏环境。因此油气集输管材的腐蚀研究有很重要的意义和应用价值。L245M钢是油气田集输管道中的常用材料,而关于这种钢材的研究内容较少,本课题着眼于研究L245M管材在油气田采集运输中的腐蚀问题,通过模拟油田采出水条件研究不同温度条件和不同醋酸浓度分别与HCO3-和Cl-对L245M钢的腐蚀影响。本文主要通过模拟浸泡实验、扫描电镜和XRD衍射分析等检测方式研究L245M管材在不同条件的腐蚀介质中腐蚀速率和产物膜的变化;利用动电位极化曲线和交流阻抗法研究管材在不同条件的腐蚀介质中的电化学特征变化情况。研究表明:温度对L245M钢的CO_2腐蚀有显著影响,在中低温阶段(≤90℃),平均腐蚀速率随着温度的升高而加快。常温下(30℃时)L245M钢在高Cl-浓度的溶液中,CO_2腐蚀主要为均匀腐蚀,当温度升高至60℃表面发现局部腐蚀,局部腐蚀反应随着温度升高而变得剧烈。在饱和CO_2的碳酸氢钠模拟水溶液中,加入醋酸会提高L245M管材的腐蚀速率,并随着醋酸浓度的增大腐蚀速率不断加快。在不含醋酸和醋酸含量较低时腐蚀产物中可以检测出碳酸亚铁的存在,当醋酸浓度达到3000ppm时,腐蚀产物中没有发现碳酸亚铁,说明醋酸浓度达到一定程度时会形成可溶解的醋酸亚铁,改变了腐蚀产物膜的化学成分。当模拟溶液中不含醋酸时,腐蚀反应主要受碳酸控制,溶液中加入醋酸时腐蚀反应受碳酸和醋酸的协同性控制,当醋酸浓度增加到2000ppm及以上时腐蚀反应主要受醋酸的控制,碳酸的作用变得微弱。在含Cl_的溶液中,醋酸会提高L245M的腐蚀速率,还会诱发L245M在较低温度下发生局部腐蚀,醋酸的加入对管材试样的腐蚀反应起促进作用。
[Abstract]:Because the environment of oil and gas field is very complex, in its exploitation and production and transportation, a large amount of corrosive medium in the environment will cause very serious corrosion to the pipeline of petroleum engineering acquisition and transportation, which will seriously affect the industrial production process. Therefore, the corrosion study of oil and gas gathering and transportation pipes is of great significance and application value. L245M steel is a common material in oil and gas field gathering pipeline, but the research content of this kind of steel is less. This paper focuses on the corrosion problem of L245M pipe in oil and gas field acquisition and transportation. The corrosion effects of HCO3- and Cl- on L245M steel at different temperatures and different acetic acid concentrations were studied by simulating oilfield produced water conditions. The changes of corrosion rate and product film of L245M pipe in different conditions were studied by scanning electron microscopy and XRD diffraction analysis. The electrochemical characteristics of pipes in different corrosion media were studied by potentiodynamic polarization curve and AC impedance method. The results show that temperature has a significant effect on the CO_2 corrosion of L245M steel. At the middle and low temperature (鈮，

本文编号：1590036