Optimization of Culture Conditions for Protein Induced Foam Production by Pseudomonas Aeruginosa for Enhancing Oil Recovery

Abstract

More than 60 % of oil in oil reservoir cannot be recovered by conventional techniques due to several factors. Permeability heterogeneity in oil reservoir is one of the factors and oil can be easily left in low permeability region in oil reservoir. Foam decreases the fluid flow in high permeability region so that fluid flow in low permeability region can be relatively increased, which enhances oil recovery from low permeability region. This study investigated the culture conditions for promoting the protein induced foam production by Pseudomonas aeruginosa for enhancing oil recovery.O2 nanobubble was examined as an O2 source for P. aeruginosa that is aerobe to make it to produce the protein-induced foam in anaerobic oil reservoir. CO2 nanobubbles were also examined as a comparison. The production of both protein and foam was evaluated through the culture experiments using glucose-based culture medium containing the nanobubbles. Production of both protein and foam by P. aeruginosa was increased not only in the culture medium containing O2 nanobubbles but also the culture medium containing CO2 nanobubbles as shown in Figure 1. Zeta potential of CO2 nanobubbles was positive in the culture medium while that was negative in pure water, therefore, CO2 nanobubbles were assumed to adsorb the cations contained in the culture medium. Because those cations were actively delivered to the bacterial cells by CO2 nanobubbles, the production of protein and foam was promoted in the culture medium containing CO2 nanobubbles. Our additional experiments clarified that ferrous ions which were delivered to the bacteria by CO2 nanobubbles promoted the production of both protein and foam by P. aeruginosa and the optimal concentration of ferrous sulfate was 0.6 mg/L (see Figure 2).Those results indicate that P. aeruginosa can be used for enhancing oil recovery as a protein induced foam producer.