Performance of Biosurfactant Produced From Pineapple Waste for Improving Oil Recovery

Abstract

Synthetic chemical surfactants have been found to be usually toxic and hardly degraded by microorganisms. Hence, attention had been shown towards biosurfactants due to their biocompatibility, lower toxicity, higher stability, stability to extreme temperature and pH. This study evaluated biosurfactant produced from pineapple waste for enhanced oil recovery using hydrocarbon utilizing bacteria from heavy oil contaminated soil. The main biosurfactant producing bacteria isolates obtained were Bacillus sp. 73S, Bacillus sp 73M, Bacillus sp 69B, Pseudomonas sp. S3 and Pseudomonas sp S9.  Routine core analyses and capillary pressure measurements were determined for core samples retrieved from the Niger-Delta sandstones. Oil recovery efficiency was measured from surface tension and surfactant adsorption measurements and the recovery performance was compared. Average porosities of the core samples ranged between 26 and 27%, air permeability from 152.96 to 232.725md, while the initial water saturation were 90.9 and 75% respectively; crude oil saturation before coreflooding were 80% and 59.45% respectively. Irreducible water saturations were 6.5 and 47% of the initial water in place respectively. Adsorption of surfactants after 24 hours for chemical and biosurfactant showed an increase in surface tension by 3.4 and 5.8dynes/cm respectively. Percentage oil recovered was found to be 87.2% for the biosurfactant while the chemical surfactant increased recovery by 67% in the sandstone formation. Biosurfactants showed higher effectiveness when it comes to surface tension and interfacial tension reduction than the chemical surfactants; hence increase in capillary number and oil recovery.  However, the chemical surfactant showed more stability with time than the biosurfactants.