To maintain the integrity of the internal surfaces of the pipelines in oil and gas industry, chemicals, including corrosion inhibitors and biocides, are commonly dosed to prevent corrosion. Imidazoline and its derivatives are widely used corrosion inhibitors for the protection of oil pipelines, which have been shown effective in reducing general corrosion. As an effective biocide, free nitrous acid (FNA) is suitable to inhibit microbially influenced corrosion, induced by for example sulfate-reducing bacteria. In this paper, we hypothesize that the continuous addition of imidazoline and intermittent dosing of FNA, when used in combination, would yield effective control of both general and pitting corrosions. As a typical imidazoline derivative, N-b-hydroxyethyl oleyl imidazoline (HEI-17) was applied in conjunction with intermittent dosing of FNA in the experimental system, with the results compared with two control systems, one receiving HEI-17 only, and one receiving no chemical dosing. The corrosion properties were monitored with open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance, 3D optical profiling, and weight-loss measurement. Following a single dose of FNA, the general corrosion rates in the experimental reactor dropped up to 50% of that in the reactor receiving continuous HEI-17 dosing (0.27 ± 0.04 vs. 0.54 ± 0.08 mm/y), but gradually recovered to 93.4% of that in 2.5 months. After the FNA treatment, the pitting corrosion was decreased by 64.6% compared with continuous HEI-17 dosing reactor for a month from measuring the cumulative distribution of the pitting depth. HEI-17 treatment alone showed moderate pitting corrosion inhibition effect (approx. 27%), and the FNA treatment inhibited the formation of deep pits effectively. The combined application of HEI-17 and FNA has shown synergistic effects and high efficiency in mitigating MIC in the simulated water injection system. This treatment strategy has strong potential to be applied in the practical oilfield operations.

为了保持石油和天然气工业中管道内表面的完整性，通常会添加化学药品（包括缓蚀剂和杀生物剂）以防止腐蚀。咪唑啉及其衍生物是广泛用于石油管道保护的腐蚀抑制剂，已被证明能有效地减少一般腐蚀。作为有效的杀生物剂，游离亚硝酸（FNA）适合抑制微生物影响的腐蚀，例如由硫酸盐还原细菌引起的腐蚀。在本文中，我们假设连续结合使用咪唑啉和间歇剂量的FNA可以有效控制一般腐蚀和点蚀。作为典型的咪唑啉衍生物，在实验系统中，将Nb-羟乙基油基咪唑啉（HEI-17）与FNA的间歇给药结合使用，结果与两个对照系统（一个仅接受HEI-17，另一个不接受化学剂量）相比。通过开路电势，电化学阻抗谱，线性极化电阻，3D光学轮廓分析和失重测量来监测腐蚀性能。单一剂量的FNA后，实验堆中的一般腐蚀速率下降至接受连续HEI-17剂量的反应堆中一般腐蚀速率的50％（0.27±0.04对0.54±0.08 mm / y），但逐渐恢复至93.4 2.5个月的百分比。FNA处理后，点蚀降低了64。从测量点蚀深度的累积分布来看，与连续一个HEI-17定量给料反应器相比，持续了一个月的时间为6％。单独的HEI-17处理显示出中等的点腐蚀抑制效果（约27％），FNA处理有效地抑制了深点的形成。HEI-17和FNA的组合应用在减轻模拟注水系统中的MIC方面显示出协同效应和高效。这种处理策略在实际的油田作业中具有很强的潜力。HEI-17和FNA的组合应用在减轻模拟注水系统中的MIC方面显示出协同效应和高效。这种处理策略在实际的油田作业中具有很强的潜力。HEI-17和FNA的组合应用在减轻模拟注水系统中的MIC方面显示出协同效应和高效。这种处理策略在实际的油田作业中具有很强的潜力。