L245NS管线钢在含硫油田环境下电化学腐蚀行为研究  

Study on Electrochemical Corrosion Behavior of L245NS Pipeline Steel in Sulfur-containing Oilfield Environment

作　　者：李鑫[1,2] 秦霖 尹志福[2] 吴东军 张佳 白巧燕 郑帅 LI Xin;QIN Lin;YIN Zhi-fu;WU Dong-jun;ZHANG Jia;BAI Qiao-yan;ZHENG Shuai(Qilicun Oil Plant,Yanchang Oil Field Co.,Ltd.,Yan'an Shaanxi 716000,China;School of Mechanical and Material Engineering,Xi'an University,Xi'an Shaanxi 710065,China)

机构地区：[1]延长油田股份有限公司七里村采油厂,陕西延安716000 [2]西安文理学院机械与材料工程学院,陕西西安710065

出　　处：《当代化工》2022年第3期581-584,共4页Contemporary Chemical Industry

基　　金：陕西省教育厅重点科学研究计划,空气泡沫驱注采井腐蚀规律、机理研究与防护体系构建(项目编号:21JS035);国家科技重大专项,大型油气田及煤层气开发(项目编号:2018ZX05059-004)。

摘　　要：通过动电位极化扫描和电化学交流阻抗方法,研究了L245NS 管线钢在含硫油田地面集输环境下的电化学腐蚀行为,并拟合分析了腐蚀热动力学参数。结果表明:(1) L245NS 管线钢在 0.1% NaCl 或 5%NaCl+饱和 CO_(2)基础介质中加入含硫物质后,极化曲线的腐蚀电流密度(i_(corr))增大显著;介质中 Cl^(-)浓度增大 i_(corr)值增大,对比含硫介质中 Cl^(-)浓度增大 i_(corr)值却有所降低。(2) Nyquist 谱含中高频区的容抗和低频区的 Warburg阻抗扩散的特征,加入含硫物质后中高频区的容抗弧显著减小,R_(t)值降低显著,Z_(w)值减小。(3)在低 Cl^(-)浓度介质中引入较低含硫物质后,会促进对碳钢的 CO_(2)腐蚀,而在较高 Cl^(-)浓度介质中引入较低含硫物质后,则对腐蚀有所减缓。The electrochemical corrosion behavior of L245NS pipeline steel in the gathering and transportation environment of the sulfur-containing oil fields was studied. The corrosion thermodynamic parameters were fitted and analyzed by potentiodynamic polarization scanning and electrochemical impedance spectroscopy methods. The results showed that corrosion current density (i_(corr)) of polarization curves of L245NS pipeline steel significantly increased in the basic medium containing 0.1% NaCl or 5% NaCl + saturated CO_(2). The i_(corr)value increased with the increase of Cl^(-)concentration in the medium, but decreased with the increase of Cl^(-)concentration in the sulfur-containing medium. Secondly, Nyquist spectra contained the capacitance arc in the mid-high frequency region and the Warburg impedance diffusion in the low frequency region, and the capacitive reactance arc in the middle and high frequency region decreased significantly with the addition of sulfur-containing substances, and the R_(t) value decreased significantly, and the Z_(w) value decreased. Thirdly, the introduction of low sulfur content into low Cl^(-)concentration medium would promote the CO_(2) corrosion of carbon steel, while it would slow down the corrosion in high Cl^(-) concentration medium.

关 键 词：L245NS管线钢 CO_(2)/H_(2)S腐蚀 极化曲线 交流阻抗 

分 类 号：TE983[石油与天然气工程—石油机械设备]