油藏铁还原微生物的研究进展

Progress of Fe (Ⅲ)-reducing microorganisms in petroleum reservoirs

地下深部油藏通常为高温、高压以及高盐的极端环境,含有非常丰富的本源嗜热厌氧微生物,按代谢类群可分为发酵细菌、硫酸盐还原菌、产甲烷古菌和铁还原菌。从油田环境已经分离出90株铁还原微生物,如热袍菌目、热厌氧杆菌目、脱铁杆菌目、δ-变形菌纲脱硫单胞菌目、γ-变形菌纲希瓦氏菌属和广古菌门栖热球菌属等,这些菌株生长温度范围为4-85°C,生长盐度范围为0.1%-10.0%NaCl,还未见到文献报道油藏铁还原菌的耐压性研究。在油藏环境中存在微生物、矿物和流体(油/水)三者之间的相互作用,油藏中的粘土矿物能够作为微生物生命活动的载体,也能为微生物代谢作用提供电子受体。本文综述了油藏铁还原菌分离和表征的研究进展,简述了油藏铁还原菌的环境适用性,并展望了铁还原菌在提高原油采收率方面的应用前景。

Oil reservoirs are often deep subsurface extreme environments with high temperatures,pressures, and salinities. Several physiological and taxonomic groups of thermophilic anaerobic bacteria are present in the oil reservoirs, such as fermentative, methanogenic, sulfate-reducing and Fe(Ⅲ)-reducing microorganisms. A total of 90 strains of Fe(Ⅲ)-reducing bacteria have been isolated from oilfield fluids and identified as the genus Thermotoga, Thermoanaerobacter, Deferribacteres, the order Desulfuromonadales within the class Deltaproteobacteria, the order Shewanella within the class Gammaproteobacteria, and Thermococcus within the Euryarchaeota, in the growth temperature range of4-85 °C and the growth salinity range of 0.1%-10% NaCl. The growth pressure range of Fe(Ⅲ)-reducing microorganisms in oil reservoirs has not been reported yet. There is strong interaction among the microorganisms, minerals and fluids(oil/water) at the actual reservoir conditions. The clay minerals can serve as carriers for microbial life activities and also provide electron acceptors for microbial metabolism.Here, we present the current status of isolation and characterization of Fe(Ⅲ)-reducing bacteria in oil reservoirs, describe the environmental applicability of Fe(Ⅲ)-reducing bacteria, and predict microbial enhanced oil recovery(MEOR) application prospects by using Fe(Ⅲ)-reducing bacteria.