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CO2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，CO2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CO2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 complicated, in the exploitation and production of transportation, a large number of corrosive media in the environment will cause serious corrosion to the transportation pipeline, which affects the industrial production process seriously and bring huge losses to the social economy , also destroying the environment. Therefore, the study of corrosion of oil and gas gathering and transportation pipe has very important significance and application value. L245M carbon steel is a pipeline widely used in oilfield, and the research content of this kind of steel is less. This topic focuses on the corrosion problem of L245M pipe in oil and gas field acquisition and transportation, and studies the different temperature Corrosion effects and different acetic acid concentrations on the corrosion of L245M steel with HCO3- and Cl- respectively. In this paper, the corrosion rate and the change of the product film of the L245M pipe under different conditions were studied by simulating immersion experiment, scanning electron microscope and XRD diffraction analysis. The effects of the potential polarization curve and the AC impedance method on the mechanical properties of the L245 M Changes of electrochemical characteristics in corrosive media. The results show that the temperature has a significant effect on the CO2 corrosion of L245M steel. The average corrosion rate increases with the increase of temperature in the low temperature stage (≤90℃). At room temperature (at 30℃) L245M steel in high Cl-concentration solution, CO2 corrosion is mainly uniform corrosion, when the temperature rises to 60℃, the local corrosion was found on surface, and the local corrosion reaction becomes severe with the temperature rised. In the saturated aqueous solution of sodium bicarbonate, adding acetic acid will increase the corrosion rate of L245M pipe, and with the increase of acetic acid concentration corrosion rate is also accelerating. In the absence of acetic acid and when the acetic acid content is low, the corrosion products can be detected in the presence of ferrous carbonate, when the acetic acid concentration increased to 3000ppm, the corrosion products was not found in ferrous carbonate, indicating that acetic acid concentration to a certain extent will form a soluble Ferrous acetate, changed the chemical composition of the corrosion product film. When the acetic acid concentration increased to 2000ppm and above, the corrosion reaction is mainly controlled by acetic acid, and the corrosion reaction is controlled by acetic acid. The role of carbonic acid becomes weak. In the solution containing Cl-, acetic acid will increase the corrosion rate of L245M, and also induce the local corrosion of L245M at lower temperature. The addition of acetic acid can promote the corrosion reaction of the pipe sample.