Exploiting Microbes in the Petroleum Field: Analyzing the Credibility of Microbial Enhanced Oil Recovery (MEOR)

Abstract

Crude oil is a major energy source that is exploited globally to achieve economic growth. To meet the growing demands for oil, in an environment of stringent environmental regulations and economic and technical pressure, industries have been required to develop novel oil salvaging techniques. The remaining ~70% of the world’s conventional oil (one-third of the available total petroleum) is trapped in depleted and marginal reservoirs, and could thus be potentially recovered and used. The only means of extracting this oil is via microbial enhanced oil recovery (MEOR). This tertiary oil recovery method employs indigenous microorganisms and their metabolic products to enhance oil mobilization. Although a significant amount of research has been undertaken on MEOR, the absence of convincing evidence has contributed to the petroleum industry’s low interest, as evidenced by the issuance of 400+ patents on MEOR that have not been accepted by this sector. The majority of the world’s MEOR field trials are briefly described in this review. However, the presented research fails to provide valid verification that the microbial system has the potential to address the identified constraints. Rather than promising certainty, MEOR will persist as an unverified concept unless further research and investigations are carried out.

Top‐down enrichment of oil field microbiomes to limit souring and control oil composition during extraction operations

“…These bacteria are collectively known to produce CO 2 and H 2 gases as well as acetic, lactic, butyric, and propionic acids that have roles in MEOR. 17,25,41 The increasing pressure and drop in pH imply that the production of some or all of these was stimulated by nutrient supplementation. However, production of H 2 S by Campylobacteria, such as Sulfurospirillium and Malaciobacter, 43,47 may have also been stimulated.…”

“…[42][43][44][45] These populations were distinct from others in the literature, 13,37 a finding that is not unexpected given that each community is driven by un environmental conditions such as temperature, salinity, pH, nutrient availability, and oil gravity among other factors. 25 However, there is no known correlation between native microbial community and MEOR success. Therefore, we pursued in vitro functional screening to evaluate candidate wells for MEOR microbiome engineering with top-down designs.…”

“…Generally, bottom‐up design in microbiome engineering pertains to constructing communities of specific microbial species and strains with desired attributes and synergies to carry out a task or set of tasks. In MEOR, bottom‐up approaches often focus on biofilm or surfactant production via communities centered around natural and/or engineered strains of Pseudomonas , Bacillus , and Enterobacter which are able to extract up to 26% of the additional trapped oil 6,22–25 . However, the ecology of engineering communities using bottom‐up designs is very complex and developing stable communities that colonize a natural, fluid ecosystem, like that of the oil well microbiome, is exceedingly difficult 26 .…”

Up‐recycling oil produced water as the media‐base for the production of xanthan gum

“…[29] The demand for bioproducts used during advanced oil recovery operations is expected to grow significantly with oil wells aging. [30][31][32][33][34] Thus, the global market of xanthan was estimated at $897 million and is projected to reach $1.5 billion by 2026, [35] due to the growing demand for gluten-free food and beverage additives as well as byproducts for enhanced oil recovery operations.…”

pH mediated assemblage of carbon, nitrogen, and sulfur related microbial communities in petroleum reservoirs

“…Under petroleum reservoir anaerobic environments, the coexistence and/or competition of different functional microorganisms could directly affect the quality of petroleum and the efficiency of petroleum recovery. In particular, the current microbial enhanced oil recovery (MEOR) technology is widely used to extract residual petroleum from low-productivity reservoirs by converting hydrocarbons through microbial fermentation and methanogenesis ( Meslé et al, 2013 ; Quraishi et al, 2021 ). Previous studies have found that petroleum hydrocarbons can be degraded by a variety of microorganisms following a quasi-step-by-step biodegradation process ( Meslé et al, 2013 ).…”