Mechanisms Involved in Microbially Enhanced Oil Recovery

Abstract

Microbial enhanced oil recovery (MEOR) represents a possible cost-effective tertiary oil recovery method. Although the idea of MEOR has been around for more than 75 years, even now little is known of the mechanisms involved. In this study, Draugen and Ekofisk enrichment cultures, along with Pseudomonas spp. were utilized to study the selected MEOR mechanisms. Substrates which could potentially stimulate the microorganisms were examined, and l-fructose, d-galacturonic acid, turnose, pyruvic acid and pyruvic acid methyl ester were found to be the best utilized by the Ekofisk fermentative enrichment culture. Modelling results indicated that a mechanism likely to be important for enhanced oil recovery is biofilm formation, as it required a lower in situ cell concentration compared with some of the other MEOR mechanisms. The bacterial cells themselves were found to play an important role in the formation of emulsions. Bulk coreflood and flow cell experiments were performed to examine MEOR mechanisms, and microbial growth was found to lead to possible alterations in wettability. This was observed as a change in wettability from oil wet (contact angle 154 • ) to water wet (0 • ) due to the formation of biofilms on the polycarbonate coupons.

Screening of biosurfactant-producing bacteria from offshore oil and gas platforms in North Atlantic Canada

“…The Halomonas isolates were closely related to Halomonas glaciei, Halomonas neptunia, and Halomonas boliviensis. These halophilic bacteria were found at harboring locations with extreme conditions such as Antarctica, deepsea hydrothermal-vent, and hypersaline lake (Kaster et al 2012;Lazar et al 2007;Lotfabad et al 2009). The Pseudomonas isolates were closely related to Pseudomonas fluorescens which was reported producing rhamnolipid-type biosurfactants that are effective under extreme temperature, salinity, and pH (Yang et al 2006).…”

“…This strain is a good example of producer with potential to effectively reduce the interfacial tension. In addition, some P. fluorescens strains (Kaster et al 2012) and B. licheniformis strains (Yakimov et al 1997) were found with the ability to alter the wettability of the rock formation. The combing effects of Rhodococcus sp.…”

Microbial enhanced oil recovery—a modeling study of the potential of spore-forming bacteria

“…It was found that lichenysin B can lower IFT to 0.006 mN/m and has a critical micelle concentration of 10 mg/L. The effect of surfactant on recovery may be enforced when bacteria are present [32,36]. The surfactant considered in our model will be of this type.…”

Microscopic pore structure of Chang 63 reservoir in Huaqing oilfield, Ordos Basin, China and its effect on water flooding characteristics

“…(Dastgheib et al 2008;Song et al 2015) In this case, fluid seepage only occurs in the partially interconnected macro pores under the influence of the pore structure heterogeneity. Consequently, oilfield development methods that are suitable for medium and high-permeability reservoirs have encountered difficulties in ultra-low permeability reservoirs (Kaster et al 2012;Li et al 2007;Yadali and Kharrat 2010). Accordingly, much attention has been paid to analyzing the characteristics of microscopic oil-water displacement as well as identifying the movement and distribution rules of oil and water.…”