Influence of competitive exclusion on the change of reservoir microbial community structure

Abstract:

[Objective] The competitive exclusion principle has been adopted to treat the production of hydrogen sulfide in offshore S oilfield, and some achievements have been made. The study aimed to reveal the influence of competitive exclusion on reservoir microbial community structure and to investigate the factors producing differences in hydrogen sulfide treatment. [Methods] High-throughput sequencing was used to analyze the changes of different microbial community structures in low-effective wells, high-effective wells and untreated wells after the addition of nitrate and nitrite. [Results] Compared with the conditions in low-effective wells and untreated wells, the species and abundance of denitrifying bacteria and oil-degrading bacteria in high-effective wells increased by 5.23% and 24.14%, respectively. Moreover, metal ions such as Fe²⁺and Zn²⁺ were found to influence the treatment effects among different wells and the changes of microbial communities. [Conclusion] In offshore oilfields, competitive exclusion could significantly reduce the production of hydrogen sulfide, and impact the microbial community environment of the reservoir. Analysis of the microbial community structure could be used as an important indicator for evaluating the effect of hydrogen sulfide treatment, which provided technical support for treating hydrogen sulfide in offshore oilfields.