嗜热稠油油藏本源微生物多样性及提高原油采收率应用潜力

Indigenous Microbial Community Diversity and Application Potential of Enhancing Oil Recovery in Thermophilic Heavy Oil Reservoir

采用16S rRNA基因克隆文库方法研究了某85℃嗜热油藏3口油井(Y12、Y8和Y68)采出液的微生物菌群多样性。根据限制性酶切片段多态性分析(ARDRA),油井Y12、Y8和Y68分别含有29、23和45个分类操作单元(OTU)。3口油井的菌群多样性存在差异,油井Y12、Y8和Y68的优势菌分别为海杆菌(Marinobacter)(占38%)、Caenispirillum(占34%)和Prolixibacter(占37%);海杆菌、假单胞菌(Pseudomonas)、未分类细菌和肠杆菌(Enterobacter)共存于3口油井采出液中,存在的未分类细菌表明油井含有新菌。此外,该油藏还含有嗜热厌氧发酵菌、硝酸盐还原菌(NRB)和铁还原菌(IRB)。海杆菌和假单胞菌都能产生物表面活性剂,从而促进烃类溶解,降低稠油黏度和乳化分散原油;嗜热厌氧发酵菌能产酸产气;NRB能控制硫酸盐还原菌产硫化物沉淀;IRB能促进粘土矿物由蒙脱石向伊利石转化,提高地层渗透率。这些功能微生物及其代谢活动都有助于提高原油采收率,表明本源微生物提高原油采收率技术在嗜热油藏具有广阔的应用前景。

We studied the microbial community diversity of the produced fluid from three oil wells(Y12,Y8,and Y68)in a 85℃thermophilic reservoir by a 16S rRNA gene clone library method.According to amplified ribosomal DNA restriction analysis(ARDRA),the oil wells Y12,Y8,and Y68 contain 29,23,and 45 operational taxonomic units(OTU),respectively.The community diversity is different among the three oil wells.The dominant bacteria in oil wells Y12,Y8,and Y68 are Marinobacter(38%),Caenispirillum(34%),and Prolixibacter(37%),respectively.Marinobacter,Pseudomona,unclassified bacteria,and Enterobacter coexist in the produced fluid of the three oil wells,and the existence of unclassified bacteria indicates that the oil wells contain new bacteria.In addition,the reservoir contains thermophilic and anaerobic fermenting bacteria,nitrate-reducing bacteria(NRB),and iron-reducing bacteria(IRB).Both Marinobacter and Pseudomonas can produce biosurfactants to promote the dissolution of hydrocarbons,reduce the viscosity of heavy oil,and emulsify and disperse crude oil.Thermophilic and anaerobic fermenting bacteria can produce acid and gas.NRB can control sulphide precipitation produced by sulfate-reducing bacteria.IRB can promote the transformation of clay minerals from montmorillonite to illite and improve formation permeability.These functional microorganisms and their metabolic activities all contribute to the enhancement of oil recovery,which indicates that the indigenous microbial enhanced oil recovery technology has a broad application prospect in thermophilic reservoirs.