title: Temperature and injection water source influence microbial community structure in four Alaskan North Slope hydrocarbon reservoirs.
abstract: A fundamental knowledge of microbial community structure in petroleum reservoirs can improve predictive modeling of these environments. We used hydrocarbon profiles, stable isotopes, and high-density DNA microarray analysis to characterize microbial communities in produced water from four Alaskan North Slope hydrocarbon reservoirs. Produced fluids from Schrader Bluff (24-27°C), Kuparuk (47-70°C), Sag River (80°C), and Ivishak (80-83°C) reservoirs were collected, with paired soured/non-soured wells sampled from Kuparuk and Ivishak. Chemical and stable isotope data suggested Schrader Bluff had substantial biogenic methane, whereas methane was mostly thermogenic in deeper reservoirs. Acetoclastic methanogens (Methanosaeta) were most prominent in Schrader Bluff samples, and the combined δD and δ(13)C values of methane also indicated acetoclastic methanogenesis could be a primary route for biogenic methane. Conversely, hydrogenotrophic methanogens (e.g., Methanobacteriaceae) and sulfide-producing Archaeoglobus and Thermococcus were more prominent in Kuparuk samples. Sulfide-producing microbes were detected in all reservoirs, uncoupled from souring status (e.g., the non-soured Kuparuk samples had higher relative abundances of many sulfate-reducers compared to the soured sample, suggesting sulfate-reducers may be living fermentatively/syntrophically when sulfate is limited). Sulfate abundance via long-term seawater injection resulted in greater relative abundances of Desulfonauticus, Desulfomicrobium, and Desulfuromonas in the soured Ivishak well compared to the non-soured well. In the non-soured Ivishak sample, several taxa affiliated with Thermoanaerobacter and Halomonas predominated. Archaea were not detected in the deepest reservoirs. Functional group taxa differed in relative abundance among reservoirs, likely reflecting differing thermal and/or geochemical influences.
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Yvette M
authors.initials: YM
authors.lastname: Piceno
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Francine C
authors.initials: FC
authors.lastname: Reid
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Tom
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Conrad
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Bill
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Hubbard
authors.affiliation: Energy Biosciences Institute Berkeley, CA, USA ; Department of Geology, University of Illinois at Urbana-Champaign, Urbana-Champaign IL, USA.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Fouke
authors.affiliation: Production Chemistry, BP Exploration Anchorage, AK, USA.
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Graff
authors.affiliation: Production Chemistry, BP Exploration Anchorage, AK, USA.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Han
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA ; Ecological Engineering Research Program, University of the Pacific Stockton, CA, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Stringfellow
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Ecological Engineering Research Program, University of the Pacific Stockton, CA, USA.
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Hanlon
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Hu
authors.affiliation: Department of Civil and Environmental Engineering, University of Tennessee Knoxville, TN, USA.
authors.forename: Terry C
authors.initials: TC
authors.lastname: Hazen
authors.affiliation: Earth Sciences Division, Lawrence Berkeley National Laboratory Berkeley, CA, USA ; Energy Biosciences Institute Berkeley, CA, USA.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Andersen
keywords: microbiology; petroleum; phylochip; reservoir; stable isotopes