Microbial enhanced oil recovery using a biosurfactant produced by Bacillus safensis isolated from mangrove microbiota - Part I biosurfactant characterization and oil displacement test

After primary and secondary recovery operations, the majority of the original oil in place remains in the reservoir due to physical and geological limitations. Thus, increasing oil recovery yields and reducing operational costs are major goals of the oil industry and efforts are being made to develop economic methods of enhanced oil recovery. One alternative method is the use of the microbiological enhanced oil recovery method (MEOR), which uses microorganisms or their metabolites, including biosurfactants, to mobilize the oil trapped in reservoirs and increase the oil recovery factor. This study aimed to evaluate the potential of a pumilacidin produced by Bacillus safensis CCMA-560 to increase oil recovery in a laboratory scale MEOR process. This bioactive molecule was previously isolated from a mangrove, increasing its potential to contribute to a more sustainable economy and to the environment. The critical micelle concentration (CMC) of the biosurfactant was determined by surface tension and thermal gravimetric analysis (TGA) was performed to evaluate if its thermal stability is consistent with the average reservoir temperature. Surface and interfacial tension measurements were performed to investigate the interfacial activity behaviors of the biosurfactant with oil and brine. Core flood experiments showed that this biosurfactant has a great potential for chemical EOR flooding applications. The results demonstrated that an alternate injection of a 1.3 CMC biosurfactant solution and 3 wt% brine should be able to permeate through the porous media, migrate to the water/oil interface, reduce the interfacial tension (IFT), and increase the oil recovery factor by 13%. In additional, a core flood experiment was performed to study the impact of this MEOR injection on the rock properties.