Microbial Communities For Microbial Enhanced Oil Recovery In Chinese Typical Heavy Oil Reservoirs And Degradating Crude Oil

Investigating microbial resources and their potential applications on Microbial enhanced oil recovery(MEOR) in oil reservoirs are crucial and essential. In this study, Microbial communities of seven different temperatures heavy oil reservoir first were identified, and then potential bacteria for MEOR were analyzed. Additionally, using chromatography electrospray ionization mass spectrometry used in conjunction with technology and Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS) techniques to characterize the microbial flora of crude oil saturated hydrocarbons, aromatic hydrocarbons and glial asphaltenes and other effects, the mechanism of transformation of heteroatoms containing nitrogen and oxygen were investigated in the range of molecule. The main items and results of this study are as follows:(1) According to the analysis of microbial communities in the oil reservoirs with different temperature(20-80℃), microbial populations in heavy oil reservoirs were quite different. Temperature of oil reservoirs had greatest effect on microbial communities. In addition, the characteristics of crude oil and minerality of oil reservoirs were other contributions to the difference of microbial communities. However, Contributing Microbial Communities(Pseudomonas aeruginosa, Pseudomonas stutzeri, Bacillus subtilis, Acinetobacter) for Microbial Enhanced Oil Recovery were detected. Results of microbial communities also showed that bacteria having potential application on MEOR inhabited all oil reservoirs with different temperatures, which indicated MEOR could be applied in oil reservoirs.(2) Flora food chain pathway of production well T6190 from low temperature heavy oil reservoirs in Xinjiang T6190 was analyzed, that complete metabolic pathways provided a theoretical basis for microbial enhanced oil recovery techniques. Additionally, Spirochaetes was determined in all the five samples, this genus of microbes may be indigenous microorganisms in oil reservoirs.(3) Using selective medium of degradating crude oil and producing surfactants in the laboratory, 62 strains of microbes isolated from eight different reservoirs. 20 strains of Baclicus lincheniformis and 3 strains of Bacillus subtilis were applied to enhanced oil recovery, as well as the degradating crude oil bacteria Bacillus cereus and Pseudomonas stutzeri, and producing biofilm/biopolymers bacteria Enterobacter cloacae aand Arcobacter molluscorum were isolated from the heavy oil reservoirs.(4) Optimal culture screened in laboratory conditions was(100ml): molasses 2g(or corn powder 0.6g/ml),(NH4)2HPO4 0.3g, KNO3 0.2g, crude oil 2g; the number of bacteria of the culture reached 108cell/ml, and oil discharge ring diameter could reach 5cm.(5) High temperature gas chromatography(HTGC) showed that a remarkable pattern that the relative abundances of long-chain hydrocarbons decreased. Electrospray ionization(ESI) coupled to high-field Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) showed that N1-species with low carbon number increased and the relative abundances of ones with higher carbon number decreased. Thereby, the obtained results speculated biodegradation of long-chain hydrocarbons and long alkyl side chains of N1-species by microbes.