In the past years, oil and gas companies sought means to increase production efficiently to address concerns about depleting natural reserves, rising world energy demand, and fluctuating oil prices. In order to optimize production from mature oil and gas fields, Enhanced Oil Recovery (EOR) emerged as a method to extract additional oil from reservoirs after conventional recovery methods, such as natural pressure and water flooding, become less effective. Typically, primary and secondary recovery techniques leave behind a significant portion of the oil in the reservoir; up to 50-70%. EOR was developed to tackle this challenge, improving oil recovery rates and extending the life of reservoirs.
It was first introduced in the 1920s, utilizing thermal methods like steam injections to reduce oil viscosity for better flow. Then the CO₂ flooding method became more widely adopted in the 1970s during the global energy crisis when maximizing oil extraction became a priority.
As the energy sector shifted toward more sustainable practices over time, advanced methods such as microbial enhanced oil recovery (MEOR) were explored. This method utilizes microorganisms and their biodegradable bio-products, which are less toxic than synthetic surfactants and other traditional methods, including thermal and chemical injections.
MEOR requires less energy and infrastructure compared to thermal methods like steam injections, which involve high operational costs. Unlike chemical flooding, MEOR relies on naturally occurring or introduced microbes, which minimizes the need for expensive chemical additives. Besides, MEOR has a significantly lower carbon footprint compared to CO₂ flooding, as it does not rely on large-scale CO₂ injection or transportation.
Egypt produces most of its oil from matured oil fields. One of the main challenges for the Egyptian oil sector is to fulfill the rising energy demand in the coming years via improving oil recovery from these mature reservoirs. Thus, MEOR presents a viable solution by leveraging indigenous bacteria from oil reservoirs, which enhances oil recovery and minimizes environmental impact.
In this respect, researchers from the British University in Cairo explored the potential of creating biosurfactants by indigenous bacteria isolated from Egyptian oil fields in the western desert for MEOR.
They collected four crude oil samples and one formation of water from El-Fayoum in the Western Desert of Egypt to examine the capability of extracting the indigenous bacteria from these samples and to produce a biosurfactant-producing bacteria to enhance the oil recovery for these reservoirs.
Following this, nine bacterial strains were isolated and screened for biosurfactant production using different assays. Screening assays showed three promising bacterial strains that exhibited significant performance and ability to produce effective biosurfactants namely A-LB, C-LB2, and B-YM2.
These three promising bacteria strains were selected for further studies and identified through the 16S rRNA gene sequencing in Sigma Labs. 16S rRNA gene sequencing results showed that A LB, C-LB2, and B-YM2 were identified as Bacillus massiliigabonensis, Pseudomonas nitritolerans, and Aninetobacterseohaensis, respectively.
Furthermore, core flooding tests were performed and the results showed that the biosurfactant produced by Bacillus massiliigabonensis could recover 69.96% of additional oil, whereas 68.11% and 63.34% of additional oil were recovered using biosurfactants produced by Pseudomonas nitritolerans, and Aninetobacterseohaensis, respectively.
Finally, the researchers compared the biosurfactant to the chemical synthetic surfactants (Dodecyl Benzene Sul- phonic Acid Sodium Salt Purified) which showed the lowest additional oil recovery over the water flooding residual oil saturation by (61.78%), which gives validation to the produced biosurfactant over synthetic surfactants emphasizing their potential as sustainable and cost-effective alternatives for enhanced oil recovery in Egyptian oil fields.
