| In the production and transportation of oil and natural gas,microbial corrosion is a common failure method.In actual working conditions,microorganisms exist in the form of symbiosis,causing serious corrosion to oil and gas transportation pipelines.The mechanism of corrosion caused by microbial colonies after symbiosis is extremely complex and difficult to prevent.Therefore,studying the corrosion phenomenon of microbial symbiosis is of great significance to understand the actual microbial corrosion process.This paper studies the microbial corrosion mechanism of carbon steel under the symbiosis of SRB,TGB and SRB+TGB.Through the molecular biological identification of the microbial population before and after corrosion,the diversity and abundance of the symbiosis of SRB,TGB and SRB+TGB were characterized,and the classification of their phyla and genus was found.After the symbiosis,it was found that the microbial population was not just two The addition of individual microorganisms,but the detection of richer population information.After the corrosion of carbon steel,the uniform corrosion of SRB and TGB is lower than the symbiosis of SRB and TGB.CLSM observed that the maximum pitting depth of SRB and TGB were 11.2 μm and 9.6 μm,respectively,and the pitting corrosion after symbiosis was 17.8 μm.SEM analysis of the biofilm after corrosion found that the biofilm of SRB was thicker,the biofilm of TGB was the thinnest,and the thickness of biofilm after SRB+TGB symbiosis was six times that of SRB biofilm.When SRB and TGB coexist,the thicker biofilm provides an anaerobic environment for the growth of SRB.Electrochemical test analysis showed that the symbiosis of SRB and TGB significantly accelerated the corrosion of carbon steel.In summary,the symbiosis between SRB and TGB changed the microbial colony structure and produced a thicker biofilm,which allowed the growth of SRB to obtain an anaerobic environment and caused more serious corrosion. |
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