Isolating, identifying and evaluating of oil degradation strains for the air-assisted microbial enhanced oil recovery process

• Published in: PloS one Vol. 16; no. 1; p. e0243976
• Main Authors: Cheng, Mingming, Yu, Long, Gao, Jianbo, Lei, Guanglun, Zhang, Zaiwang
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 25.01.2021; Public Library of Science (PLoS)
• Subjects: Air injection; Alkanes - metabolism; Anaerobic bacteria; Bacillus - growth & development; Bacillus - isolation & purification; Bacillus - metabolism; Bacteria - growth & development; Bacteria - isolation & purification; Bacteria - metabolism; Biodegradation; Biodegradation, Environmental; Biology and Life Sciences; Carbon; Carbon sources; Decomposition (Chemistry); Dissolved oxygen; Earth Sciences; Ecology and Environmental Sciences; Engineering; Engineering and Technology; Enhanced oil recovery; Enterobacter - growth & development; Enterobacter - isolation & purification; Enterobacter - metabolism; Environmental engineering; Experiments; Fermentation; Flood predictions; Flooding; Mathematical models; Metabolism; Metabolites; Methods; Microbial enhanced oil recovery; Microorganisms; Oil; Oil and Gas Fields - microbiology; Oil recovery; Oxygen; Oxygen - metabolism; Oxygen consumption; Permeability; Petroleum; Petroleum - microbiology; Petroleum engineering; Petroleum research; Physical Sciences; Physiological aspects; Pseudomonas - growth & development; Pseudomonas - isolation & purification; Pseudomonas - metabolism; Recovery (Medical); Safety; Safety engineering; Salinity; Strains (organisms); China; Singapore
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0243976

Due to the inefficient reproduction of microorganisms in oxygen-deprived environments of the reservoir, the applications of microbial enhanced oil recovery (MEOR) are restricted. To overcome this problem, a new type of air-assisted MEOR process was investigated. Three compounding oil degradation strains were screened using biochemical experiments. Their performances in bacterial suspensions with different amounts of dissolved oxygen were evaluated. Water flooding, microbial flooding and air-assisted microbial flooding core flow experiments were carried out. Carbon distribution curve of biodegraded oil with different oxygen concentration was determined by chromatographic analysis. The long-chain alkanes are degraded by microorganisms. A simulation model was established to take into account the change in oxygen concentration in the reservoir. The results showed that the optimal dissolved oxygen concentration for microbial growth was 4.5~5.5mg/L. The main oxygen consumption in the reservoir happened in the stationary and declining phases of the microbial growth systems. In order to reduce the oxygen concentration to a safe level, the minimum radius of oxygen consumption was found to be about 145m. These results demonstrate that the air-assisted MEOR process can overcome the shortcomings of traditional microbial flooding techniques. The findings of this study can help for better understanding of microbial enhanced oil recovery and improving the efficiency of microbial oil displacement.