Abstract
This study used an exogenous lipopeptide-producing Bacillus subtilis to strengthen the indigenous microbial enhanced oil recovery (IMEOR) process in a water-flooded reservoir in the laboratory. The microbial processes and driving mechanisms were investigated in terms of the changes in oil properties and the interplay between the exogenous B. subtilis and indigenous microbial populations. The exogenous B. subtilis is a lipopeptide producer, with a short growth cycle and no oil-degrading ability. The B. subtilis facilitates the IMEOR process through improving oil emulsification and accelerating microbial growth with oil as the carbon source. Microbial community studies using quantitative PCR and high-throughput sequencing revealed that the exogenous B. subtilis could live together with reservoir microbial populations, and did not exert an observable inhibitory effect on the indigenous microbial populations during nutrient stimulation. Core-flooding tests showed that the combined exogenous and indigenous microbial flooding increased oil displacement efficiency by 16.71%, compared with 7.59% in the control where only nutrients were added, demonstrating the application potential in enhanced oil recovery in water-flooded reservoirs, in particular, for reservoirs where IMEOR treatment cannot effectively improve oil recovery.
Highlights
With the increasing global energy demand and depletion of oil reserves, oil recovery by microbial flooding is currently under intensive development, and has been shown to be economically feasible by laboratory and field trials (Belyaev et al, 1998; Gao and Zekri, 2011; Xiao et al, 2013; Li et al, 2014; Shibulal et al, 2014; Dong et al, 2015; You et al, 2015)
The microbial processes and driving mechanisms were investigated by analyzing the changes in oil properties and the interplay between the exogenous B. subtilis and indigenous microbial populations in microcosms stimulated with different kinds of nutrients
The lipopeptide-producing gene srfA detected in this strain and the Fourier transform infrared spectrometry (FTIR) spectra of the surfactant together revealed that B. subtilis M15-10-1 produced lipopeptides (Figure 3D)
Summary
With the increasing global energy demand and depletion of oil reserves, oil recovery by microbial flooding is currently under intensive development, and has been shown to be economically feasible by laboratory and field trials (Belyaev et al, 1998; Gao and Zekri, 2011; Xiao et al, 2013; Li et al, 2014; Shibulal et al, 2014; Dong et al, 2015; You et al, 2015) This technique is generally classified into exogenous and indigenous microbial enhanced oil recovery (MEOR). Because of the sieve effect of strata on microbial cells, the injected microorganisms are generally
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
