Using biosurfactant producing bacteria isolated from an Iranian oil field for application in microbial enhanced oil recovery

Abstract

Microbial enhanced oil recovery (MEOR) is a useful technique to improve oil recovery from depleted oil reservoirs beyond primary and secondary recovery operations using bacteria and their metabolites. In the present study, the biosurfactant production potential of Bacillus licheniformis microorganisms that were isolated from oil samples of Zilaei reservoir in the southwest of Iran was explored under extreme conditions. Growth media with different temperatures of 40, 50, 60, and 70°C; salinities of 1, 3, 5, and 7 wt%; and yeast extract concentrations of 0.5, 1, 1.5, and 2 g/L were used to find the optimum growth conditions. The results demonstrated that bacteria grown in a mineral salt solution with temperature of 50°C, salinity of 1 wt% and yeast extract concentration of 1 g/L has the highest growth rate and therefore, these conditions are the optimum conditions for growing the introduced bacterium. This isolate was selected as the higher biosurfactant producer. The obtained biosurfactants by bacteria isolated in a medium with these conditions could reduce the interfacial tension of crude oil/water system from 36.8 to 0.93 mN/m and surface tension of water from 72 to 23.8 mN/m. The results of the core flooding tests showed that the tertiary oil recovery efficiency due to the injection of microorganisms was 13.7% of original oil in place and bacteria could reduce the oil viscosity by 41.242% at optimum conditions. Based on these results, the isolated microorganism is a promising candidate for the development of microbial oil recovery processes.

Use of Microorganisms in the Recovery of Oil From Recalcitrant Oil Reservoirs: Current State of Knowledge, Technological Advances and Future Perspectives

“…This organism was injected in sandstone core samples and allowed to grow and excrete biosurfactants for 7 days. The amount of oil recovered in this stage was almost 14% of OOIP (Daryasafar et al, 2016). Though these studies are limited, the potential of this direct injection approach is promising, but requires more testing.…”

“…When poor oil recovery from oil wells is due to low permeability of the rock formation, or to the high viscosity of the crude oil, the ability of biosurfactants to reduce IFT between the flowing aqueous phase and the residual oil saturation can potentially improve the process efficiency and recover more oil (Banat et al, 2000). During the shut-in period, effecting an IFT reduction can significantly influence recovery of the oil during the initial stage, while later in the recovery process, both the produced biosurfactants and microorganisms -noting that microbial cells themselves can express IFT-reducing properties -can attach to the rock surface and alter its wettability (Daryasafar et al, 2016).…”

“…P. aeruginosa incubated at 37 • C produces rhamnolipids, which at a concentration of 1 mg/ml this biosurfactant has been shown to recover 22% of oil from sand-packed columns at 40 • C, and to be more effective than the chemical surfactant Petrostep (15.6% oil recovery) (Gudiña et al, 2015). B. subtilis and B. licheniformis strains have been repeatedly isolated from many oil reservoirs, as well as from oil-contaminated sites (Cooper et al, 1981;Al-Wahaibi et al, 2014;Al-Sayegh et al, 2015;Daryasafar et al, 2016). Thermophilic hydrocarbon degraders of the genera Bacillus, Thermus, Thermoanaerobacter, Thermococcus, and Thermotoga have been isolated from high temperature reservoirs in China (90 • C; Lin et al, 2014), California (80-90 • C; Orphan et al, 2000) and North Sea (70 • C; Dahle et al, 2008), and would therefore be ideal candidates for MEOR (Kaster et al, 2009).…”

“…Many species of bacteria have been shown to be halophilic (able to grow and thrive in relatively high salt concentrations), some of which with the added ability to also grow under the conditions experienced in oil reservoirs (Head et al, 2014). Strains of B. subtilis and B. licheniformis can tolerate high salt concentrations (up to 5% NaCl) and at temperatures up to 50 • C (Cooper et al, 1981;Daryasafar et al, 2016). Gordonia amicalis is able to degrade paraffins at 40 • C in the presence of 5% NaCl (Hao et al, 2008).…”

Promising Biotechnology on Selective Plugging and Wettability Alteration for Enhanced Oil Recovery

“…It affects adsorbed oil on reservoir rock by changing the interfacial tension between oil and water. Several studies have been shown that oil recovery is improved by this mechanism [21][22][23][24][25][26][27][28][29][30][31][32][33].…”