Stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery

Abstract

Low permeability oil reservoirs are a widespread petroleum reservoir type all over the world. Therefore, methods to recover these reservoirs efficiently are of importance to guarantee energy supply. Here we report our novel stimulation of indigenous microbes by optimizing the water cut in low permeability reservoirs for green and enhanced oil recovery. We aimed to investigate the characteristics of indigenous bacterial communities with changes in water cut in reservoirs by high-throughput sequencing technology, and reveal the mechanism and characteristics of the crude oil biotreatment under different crude oil-water ratio conditions and the optimum activation time of indigenous functional microbial groups in reservoirs. The indigenous microbial metabolism products were characterized by gas chromatography mass spectrometry. Results showed that Acinetobacter (47.1%) and Pseudomones (19.8%) were the main functional genus of crude oil degradation at the optimal activation time, and can reduce the viscosity of crude oil from 8.33 to 5.75 mPa·s. The dominant bacteria genus for oil recovery after activation of the production fluids was similar to those in the reservoirs with water cut of 60–80%. Furthermore seven mechanism pathways of enhancing oil recovery by the synergistic of functional microbial groups and their metabolites under different water cut conditions in low permeability reservoirs have been established.

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

“…At subsequent stages, when the quantity of oil relative to the water increases, it is no longer economical to continue the process, and the oil reserve should be abandoned [18,20,21]. Around 50% to 70% of the world's unrecoverable crude oil remains in reserves that have been exhausted by conventional methods [22][23][24]. Hence, in this paper, we focus on tertiary methods where the trapped oil is extracted for use from the existing and abandoned reserves.…”

“…Furthermore, it reduces the viscosity and pour point of the crude oil, and also contributes to oil desulfurization and emulsification, thus making MEOR strategies more favourable. Some studies have attempted to starve the microbes to minimize their size and enhance their penetration depth into the reservoir, and subsequently provide them with nutrients to form biofilms of biomass [23,64].…”

Development of Biochemically Enhanced Oil Recovery Technology for Oil Fields – A Review

“…Microbial enhanced oil recovery (MEOR) is a collection of techniques that utilise microorganisms and their metabolic products to improve the recovery of crude oil from reservoir rock (Yen, 1990;Lazar et al, 2007;Zhang and Xiang, 2010;Shibulal et al, 2014Shibulal et al, , 2018Cui et al, 2019). The recovery can either be in the form of cyclic (single-well simulation), microbial flooding, or selective plugging recovery (Lazar et al, 2007;Shibulal et al, 2014).…”

“…Enhanced oil recovery using polymer flooding and microbial enhanced oil recovery can act synergistically to solve the issues that limit efficient recovery process. In order to successfully implement enhanced oil recovery, many groups of researchers have experimentally investigated the feasibility and potential of using novel biopolymers developed through synergistic chemical and microbial technology (BcEOR) (Yen, 1990;Lazar et al, 2007;Zhang and Xiang, 2010;Shibulal et al, 2014Shibulal et al, , 2018Cui et al, 2019).…”

Desulfovibrio and Pseudomonas Dominated Enriched Produced Water Reinforcing their Importance in Oilfields and Production Processes

“…Several studies have found the occurrence of the genus Pseudomonas in oil reservoirs [71][72][73][74][75][76][77] , according to Cui et al 78 , Pseudomonas and Acinetobacter are genera that can effectively use crude oil as a carbon source, being able to survive and reproduce at the oil-water interface. Species of the genus Pseudomonas are facultative anaerobes capable of performing nitri cation and nitrate reduction using various carbon substrates 79,80 .…”