Evaluation of Microbiological Corrosion of API 5L X80 Steel by Electrochemical Techniques in Produced Water by the Oil Industry

Corrosion of pipelines can be significantly affected by the activity of microorganisms present in the environment. The objective of this work was to investigate the influence microbial in the corrosion behavior of API 5L X80 steel in produced water by open circuit potential, polarization curves and electrochemical impedance spectroscopy measurements. Physical-chemical and microbiological analyzes were performed in the produced water and the tests were conducted in biotic and abiotic systems. The films and corrosion morphology developed in the steel over time were characterized by scanning electron microscopy. The results confirm that the activity of the consortium of microorganisms in the formed biofilm accelerated the dissolution of the iron, causing pitting corrosion in the steel exposed to the biotic system. Through the adjustment of the equivalent electrochemical circuit, the impedance results allowed to interpret the interactions between electrode, film and electrolyte.管道的腐蚀行为可显著受环境中存在的微生物活动影响。本研究旨在通过开路电位、极化曲线以及电化学阻抗谱（Electrochemical Impedance Spectroscopy, EIS）测试，探究微生物对采出水中API 5L X80钢腐蚀行为的影响。研究团队对采出水开展了理化与微生物学分析，并在生物体系与非生物体系中完成了全部测试。采用扫描电子显微镜（Scanning Electron Microscopy, SEM）对不同时长下钢表面形成的腐蚀产物膜与腐蚀形貌进行了表征。结果证实，生物膜内微生物群落的活动加速了铁的溶解，致使暴露于生物体系中的钢材发生点蚀。通过拟合等效电化学电路，阻抗测试结果可用于解析电极、腐蚀产物膜与电解质之间的相互作用。