湿H_2S环境中抽油杆用合金结构钢电化学腐蚀

在油气田腐蚀的诸多影响因素中,H2S是最常见和最有害的腐蚀介质.为了向油田选材和防腐实践提供理论依据,本文采用失重法和扫描电镜分析研究了抽油杆常用合金结构钢20CrMo,20Ni2Mo和35CrMo在不同浓度及温度下的H2S腐蚀行为.研究结果表明:(1)总体而言,随着H2S浓度的增加,材料的腐蚀速率均有所增加.但在100℃时20Ni2Mo对H2S浓度的变化不敏感,且在3种材料中平均抗腐蚀性能较好;在25℃时35CrMo材料在不同H2S浓度环境中具有较好的平均耐腐蚀性.(2)随着温度的升高,在3种材料的腐蚀速率有不同程度的提高.(3)在3种材料中,20CrMo的耐蚀性最差.

Electrochemical corrosion of the structural alloy steel used for sucker rod in wet H2S environment

Among the factors of influencing the corrosion in oilfields,hydrogen sulfide is the most common and harmful corrosive medium.In order to provide theoretical basis for the material selecting and corrosion preventing of oilfields, the corrosion behavior of 20CrMo,20Ni2Mo and 35CrMo structural alloy steels under different temperature and different concentration of H_2S is studied by means of weight-loss method,and the corrosion appearance of test samples is analyzed by means of electronic scanner.The results show that,(1) overall,the corrosion rates of three materials increase with the increase of the concentration of H_2S;but at 100 ℃,the corrosion rate of 20Ni2Mo is not sensitive to the variation of the concentration of H_2S,the average corrosion resistivity of 20Ni2Mo is the best among three materials;at 25 ℃,the average corrosion resistivity of 35CrMo is the best among three materials;(2) the corrosion rates of three materials all increase with the increase of temperature;(3) the corrosion resistivity of 20CrMo is the worst among three materials.