Laboratory Investigation of Microbial Enhanced Oil Recovery

Twelve bacterial strains were isolated from Saudi crude oils and formation waters. Experimental work was conducted to identify the bacterial isolates, determine the compositions of the appropriate nutrients and carry out surface phenomena measurements. Based on the results obtained, three bacterial strains (O12, O6a, O9) were selected for displacement tests. The effects of nutrient type, bacterial type, permeability, API and salinity on oil recovery were investigated. Results show that the bacterial strains O12 and O6a were found to produce biogases and biosurfactants. Biopolymers were produced by O9. The greatest oil recovery was obtained from activation of the indigenous bacteria by 1% molasses concentration. Injection of the bacterial strains O9 and O6a in glucose or sucrose media resulted in a higher recovery of oil. No effects on oil recovery was observed upon changing permeability from 453 to 3736 md and salinity from 4.2 to 10% of total dissolved salt.