目的 通过实验模拟L360N管线钢在致密气油水共存条件下的微生物腐蚀(MIC)行为，探究凝析油对MIC行为的影响。方法 模拟6组凝析油体积占比不同的腐蚀环境，结合失重测试和电化学实验分析了凝析油对腐蚀速率的影响规律。通过最大可能计数法(MPN法)计数试片表面的细菌固着量。采用激光显微镜、扫描电镜(SEM)、能谱仪(EDS)、光电子能谱仪(XPS)表征分析腐蚀形态和产物形貌、成分。结果 凝析油溶于水中会直接影响微生物腐蚀行为。水中存在的凝析油可显著降低L360N管线钢的均匀腐蚀速率，但不同条件下浸泡的试片表面均有明显的点蚀。所有试片表面的细菌固着量都不低于10⁴ cells/cm²，且都有生物膜形成，主要化学成分是Fe2O3和FeS。另外，在高凝析油体积占比条件下，膜内的硫化物更倾向于局部沉积，使得生物膜结构更加不均匀。电化学测试表明，随着时间的延长，各条件下的电荷转移电阻(Rct)和腐蚀电流密度(Jcorr)都变化至相近水平，凝析油含量升高不能长期抑制膜下固着菌的代谢活性。结论 L360N管线钢在不同凝析油体积占比的油水介质中均有MIC发生。其原因在于凝析油含量升高不能完全抑制生物膜的形成，还促使生物膜结构更加不均匀，为固着菌代谢提供了适宜的环境，有利于点蚀的发生。

The microbiologically influenced corrosion (MIC) behavior of L360N pipeline steel was studied in simulated tight gas produced water mixed with condensate. The effect and mechanism of condensate on MIC behavior was explored by conducting experiments. Six groups of static immersion tests were carried out under different volume proportions of mixed condensate, and the condensate concentration dissolved in water was measured by gravimetric method. The MPN method was used to count sessile cells settled on coupon surface. The weight-loss and electrochemical measurements were applied to study the influence of condensate on the corrosion rate and mechanism of L360N pipeline steel. The laser microscope was used to analyze pit depth of coupons after removal of corrosion product. Investigation of the surface and cross-sectional morphology of corrosion product was conducted by SEM. EDS and XPS were used to analyze the composition of corrosion product. The MIC behavior was closely affected by the dissolution of condensate. And the condensate concentration in water increased as volume proportion of condensate rose. The general corrosion rates in the presence of condensate were much lower than those without it. But the occurrence of pitting corrosion was observed for all coupons under different conditions. It indicated that the presence of condensate had a limited inhibition effect on pitting corrosion. With the existence of dissolved condensate, there were still a large amount of sessile cells at above 104 cells/cm2 for both SRB and FB. The SEM analysis showed that all coupons were covered with biofilms with the composition of Fe2O3 and FeS. It suggested that the metabolic activity could not be completely prevented by the increase of condensate concentration, and the MIC was caused for all conditions. From EDS analysis, the significant difference in S mass fraction was found among different analysis regions for the same coupon. It indicated the increase of condensate concentration contributed to the formation of more heterogeneous biofilms because of inhomogeneous distribution of sulfide, which was one of the reasons for pitting corrosion occurrence. It could be seen from electrochemical measurements that although the electron transfer resistance (Rct) obtained under various conditions showed different levels, Rct and corrosion current density (Jcorr) for all conditions had similar orders of magnitude at the end of testing. It demonstrated that the increase of condensate might promote MIC inhibition at the start of immersion, but could not consistently hinder bacteria metabolism. The influence of condensate on MIC behavior of L360N pipeline steel in simulated tight gas produced water was revealed. The MIC occurred for all conditions and caused pitting corrosion. The reason for it was that the complete biofilm was formed on all coupons surface that exposed to simulated produced water with different concentration of condensate. Then the conformable environment under it was created for sessile cells to survive. Therefore, the metabolize of sessile cells was increasingly enhanced and localized corrosion battery was formed gradually. And the increase of condensate concentration led to the formation of biofilms with more heterogeneous structure, which could be one of mechanisms about pitting corrosion induced by MIC as well.