Microbial community composition of a hydrocarbon reservoir 40 years after a CO2 enhanced oil recovery flood

Jenna L.K. Shelton, Robert S. Andrews, Denise M. Akob, Christina A. DeVera, Adam Mumford, John E. McCray, Jennifer McIntosh

Research output: Contribution to journalArticle

Abstract

Injecting CO2 into depleted oil reservoirs to extract additional crude oil is a common enhanced oil recovery (CO2-EOR) technique. However, little is known about how in situ microbial communities may be impacted by CO2 flooding, or if any permanent microbiological changes occur after flooding has ceased. Formation water was collected from an oil field that was flooded for CO2-EOR in the 1980s, including samples from areas affected by or outside of the flood region, to determine the impacts of CO2-EOR on reservoir microbial communities. Archaea, specifically methanogens, were more abundant than bacteria in all samples, while identified bacteria exhibited much greater diversity than the archaea. Microbial communities in CO2-impacted and non-impacted samples did not significantly differ (ANOSIM: Statistic R = -0.2597, significance = 0.769). However, several low abundance bacteria were found to be significantly associated with the CO2-affected group; very few of these species are known to metabolize CO2 or are associated with CO2-rich habitats. Although this study had limitations, on a broad scale, either the CO2 flood did not impact the microbial community composition of the target formation, or microbial communities in affected wells may have reverted back to pre-injection conditions over the ca. 40 years since the CO2-EOR.

Original languageEnglish (US)
Article numberfiy153
JournalFEMS Microbiology Ecology
Volume94
Issue number10
DOIs
StatePublished - Oct 1 2018

Keywords

  • Bioinformatics
  • Carbon dioxide enhanced oil recovery
  • Carbon sequestration
  • Microbial ecology

ASJC Scopus subject areas

  • Microbiology
  • Ecology
  • Applied Microbiology and Biotechnology

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