Microbial Diversity Analysis of Reservoirs After Polymer Flooding in Daqing Oil Field at the Middle Stage of Microbial Profile Modification

摘要

To gain a better understanding of the mechanism and technology of microbial enhanced oil recovery, microbial community structure and diversity of reservoirs after polymer flooding in Daqing oil field at the Middle Stage of microbial profile modification were studied. Research methodology: DNA was extracted from four oil well samples after polymer flooding in the Daqing Oilfield, Heilongjiang, China. A 16S rDNA clone library was constructed by PCR amplification with universal primers. Research result: 101 clones were obtained and classified into 9 different operational taxonomic units (OTUs). Four OTUs had more than five clones occupied most of the 16S rDNA clone library, while 5 OTUs had only one clone. At the same time, the microbial diversity of the 16S rDNA clone library was evaluated by coverage value (C), Shannon-Weiner index (H) and Margalef index (M). Phylogenetic analysis revealed that the dominant microbes of the library belonged to uncultured bacteria (55%). Cultured bacteria are composed of Alphaproteobacteria (3%), Gammaproteobacteria (35%), Deltaproteobacteria (4%) and Epsilonproteobacteria (1%). The Pseudomonas related with hydrocarbon biodegradation and surfactant production accounted for 25 % in the clone library.