Dominance of Desulfotignum in sulfate-reducing community in high sulfate production-water of high temperature and corrosive petroleum reservoirs

• α, γ-proteobacteria, Archaeoglobi, and Methanomicrobia were the most abundant phylotypes in the production water samples.
• dsrA gene based analysis showed that Desulfotignum spp. were the most encountered SRP in the studies samples.
• This study provides a basis for research on controlling reservoir souring and biocorrosion in oil production systems.

Petroleum reservoirs souring and pipelines corrosion are severe in Jiangsu Oilfield of China, and microorganisms have a major role in the related problems. This study revealed the microbial diversity and composition of both bacteria and archaea by using 16S rRNA gene clone library method, and those of sulfate-reducing prokaryotes (SRP) by dissimilatory sulfate reductase α-subunit encoding gene (dsr) clone library in two different samples of high temperature petroleum reservoirs containing high concentration of sulfate and with known corrosion. In addition, the abundance of bacteria and SRP in the samples was quantified by real-time PCR assays based on 16S rRNA and dsr genes. The results showed that both production water samples from Wei 2-53 and Wei 11-7 wells exhibited very rich bacterial diversity, and both Gammaproteobacteria and Alphaproteobacteria were the main abundant ones. Thioalkalivibrio-related species belonging to Gammaproteobacteria were also observed in both of them. Methanomicrobia, Archaeoglobi and Thermococci were common archaea in these samples, with Archaeoglobus as the dominant genus in both of them. The dsrA libraries analysis showed that a low diversity of sulfidogenic communities with Desulfotignum spp. as the most dominant SRP in the samples. The data reported here enhance our knowledge on microbial community and abundance including SRP in high temperature and corrosive reservoirs, providing a better basis for further research on and management control of reservoir souring and biocorrosion in oil production systems.