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

FEMS Microbiology Ecology

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https://doi.org/10.1093/femsec/fiy153

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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.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Microbial community composition of a hydrocarbon reservoir 40 years after a CO2 enhanced oil recovery flood
Series title:
FEMS Microbiology Ecology
DOI:
10.1093/femsec/fiy153
Volume:
94
Issue:
10
Year Published:
2018
Language:
English
Publisher:
Oxford University Press
Contributing office(s):
Eastern Energy Resources Science Center
Description:
fiy153; 11 p.
First page:
1
Last page:
11
Country:
United States
State:
Louisiana