title: Microbial abundance and community composition influence production performance in a low-temperature petroleum reservoir.
abstract: Enhanced oil recovery using indigenous microorganisms has been successfully applied in the petroleum industry, but the role of microorganisms remains poorly understood. Here, we investigated the relationship between microbial population dynamics and oil production performance during a water flooding process coupled with nutrient injection in a low-temperature petroleum reservoir. Samples were collected monthly over a two-year period. The microbial composition of samples was determined using 16S rRNA gene pyrosequencing and real-time quantitative polymerase chain reaction analyses. Our results indicated that the microbial community structure in each production well microhabitat was dramatically altered during flooding with eutrophic water. As well as an increase in the density of microorganisms, biosurfactant producers, such as Pseudomonas, Alcaligenes, Rhodococcus, and Rhizobium, were detected in abundance. Furthermore, the density of these microorganisms was closely related to the incremental oil production. Oil emulsification and changes in the fluid-production profile were also observed. In addition, we found that microbial community structure was strongly correlated with environmental factors, such as water content and total nitrogen. These results suggest that injected nutrients increase the abundance of microorganisms, particularly biosurfactant producers. These bacteria and their metabolic products subsequently emulsify oil and alter fluid-production profiles to enhance oil recovery.
authors.affiliation: Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, P.R. China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Li
authors.forename: Peike
authors.initials: P
authors.lastname: Gao
authors.forename: Yunqiang
authors.initials: Y
authors.lastname: Wu
authors.forename: Huimei
authors.initials: H
authors.lastname: Tian
authors.forename: Xuecheng
authors.initials: X
authors.lastname: Dai
authors.forename: Yansen
authors.initials: Y
authors.lastname: Wang
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Cui
authors.forename: Hongzuo
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Pan
authors.forename: Hanping
authors.initials: H
authors.lastname: Dong
authors.forename: Ting
authors.initials: T
authors.lastname: Ma
mesh_terms: D000421:Alcaligenes / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002681:China; D003080:Cold Temperature; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D004655:Emulsions; D010578:Petroleum / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification / Q000235:genetics / Q000378:metabolism; D012240:Rhodococcus / Q000145:classification / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D013696:Temperature; D014867:Water / Q000737:chemistry; D014871:Water Microbiology
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D004655:Emulsions; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D014867:Water