Microbial Diversity of the Produced Waters from the Oilfields in the Republic of Tatarstan (Russian Federation): Participation in Biocorrosion

A variety of microorganisms grow in oil reservoirs, where they participate in the biodegradation of oil and lead to changes in oil quality. Today, our knowledge about microbial processes in oil reservoirs is largely limited, and among the urgent tasks for the oil industry, monitoring and controlling microbial activity (including the activity of microbes responsible for biocorrosion) are important. In this work, we aimed to characterize the bacterial community structure of the produced waters from oilfields in the south of the Republic of Tatarstan (Russian Federation) using cultural and molecular methods of analysis. Bacteria from produced water samples from various oil wells were enriched, and 16S rRNA gene amplicon sequencing was used to assess the phylogenetic diversity of the bacterial communities. Thus, analysis of the bacterial communities revealed the presence of various members within the genera Desulfotomaculum, Clostridium, Acetobacterium, Desulfovibrio, Dethiosulfovibrio, Desulfomicrobium, Fusibacter, Dethiosulfatibacter, Thermovirga, Sphaerochaeta, and Desulfoplanes, but in different produced water samples. The role of the bacterial associations in biocorrosion was separately assessed in experiments on monitoring and stimulating biocorrosion. The bacterial community receiving additional nutrition was shown to have a higher corrosion potential, and scanning electron microscopy analysis confirmed changes in the surface of the metal coupons during immersion testing. The practical value of this research lies in identifying the potential contribution of microbial communities to oil pipeline corrosion.