title: Methods for recovery of microorganisms and intact microbial polar lipids from oil-water mixtures: laboratory experiments and natural well-head fluids.
abstract: Most of the world's remaining petroleum resource has been altered by in-reservoir biodegradation which adversely impacts oil quality and production, ultimately making heavy oil. Analysis of the microorganisms in produced reservoir fluid samples is a route to characterization of subsurface biomes and a better understanding of the resident and living microorganisms in petroleum reservoirs. The major challenges of sample contamination with surface biota, low abundances of microorganisms in subsurface samples, and viscous emulsions produced from biodegraded heavy oil reservoirs are addressed here in a new analytical method for intact polar lipids (IPL) as taxonomic indicators in petroleum reservoirs. We have evaluated the extent to which microbial cells are removed from the free water phase during reservoir fluid phase separation by analysis of model reservoir fluids spiked with microbial cells and have used the resultant methodologies to analyze natural well-head fluids from the Western Canada Sedimentary Basin (WCSB). Analysis of intact polar membrane lipids of microorganisms using liquid chromatography-mass spectrometry (LC-MS) techniques revealed that more than half of the total number of microorganisms can be recovered from oil-water mixtures. A newly developed oil/water separator allowed for filtering of large volumes of water quickly while in the field, which reduced the chances of contamination and alterations to the composition of the subsurface microbial community after sample collection. This method makes the analysis of IPLs (or indirectly microorganisms) from well-head fluids collected in remote field settings possible and reliable. To the best of our knowledge this is the first time that IPLs have been detected in well-head oil-water mixtures.
authors.affiliation: Petroleum Reservoir Group, Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada. toldenbu@ucalgary.ca
authors.forename: Thomas B P
authors.initials: TB
authors.lastname: Oldenburg
authors.forename: Steve R
authors.initials: SR
authors.lastname: Larter
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Adams
authors.forename: Melisa
authors.initials: M
authors.lastname: Clements
authors.forename: Casey
authors.initials: C
authors.lastname: Hubert
authors.forename: Arlene K
authors.initials: AK
authors.lastname: Rowan
authors.forename: Angela
authors.initials: A
authors.lastname: Brown
authors.forename: Ian M
authors.initials: IM
authors.lastname: Head
authors.forename: Aleksandr A
authors.initials: AA
authors.lastname: Grigoriyan
authors.forename: Gerrit
authors.initials: G
authors.lastname: Voordouw
authors.forename: Milovan
authors.initials: M
authors.lastname: Fustic
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D001673:Biodegradation, Environmental; D002853:Chromatography, Liquid; D017753:Ecosystem; D008055:Lipids / Q000737:chemistry* / Q000302:isolation & purification; D008828:Microbiological Techniques; D010578:Petroleum; D044367:Phase Transition; D021241:Spectrometry, Mass, Electrospray Ionization; D014867:Water / Q000737:chemistry*; D014871:Water Microbiology
chemical_list: D008055:Lipids; D010578:Petroleum; D014867:Water