Abstract
The inadequacy of worldwide fossil fuel resources, combined with increasing energy demands, encourages global attention to either using alternative energy resources or improving the recovery factor and produce larger quantities from present reservoirs. Among all enhanced oil recovery (EOR) methods, surfactant injection is a well-known technique that reduces the interfacial tension (IFT) between oil and water and increases oil production. Despite numerous advantages of using surfactants, there are also a few obstacles like environmental impacts, high cost, effect on humans and other organisms due to toxicological potential, and availability from nonrenewable resources. Biosurfactants are microbial surface-active agents that decrease the surface tension (ST) of a liquid phase and the IFT of two diverse phases. They are biotechnological products of high value owing to their widespread applications, low toxicity, relatively easy preparation, and specific performance, applied in different industries like organic chemicals and fertilizers, agrochemicals, metallurgy and mining, cosmetics, foods, medical and pharmaceuticals, beverages, environmental management, and petroleum and petrochemical applications in emulsifying and demulsifying wetting agents, detergent spreading and foaming agents, and functional food ingredients. Biosurfactants are synthesized by microbes; therefore, various genetic diversities of microorganisms provide the considerable capability to produce new types of biosurfactants, which can develop EOR technology. Biosurfactants are classified into ex situ and in situ MEOR processes. The genera Pseudomonas, Bacillus, Sphingomonas, and Actinobacteria are the foremost biosurfactant-producing bacteria. This paper reviews relevant reports and results from various presented papers by researchers and companies on applications of microorganisms and biosurfactant technology with specific emphasis on EOR and MEOR processes, based on recently published articles since 2010 until now.
Highlights
Academic Editor: Alireza Baghban e inadequacy of worldwide fossil fuel resources, combined with increasing energy demands, encourages global attention to either using alternative energy resources or improving the recovery factor and produce larger quantities from present reservoirs
Biosurfactants are a group of amphiphilic compounds with antiviral, hemolytic, insecticidal, and antimicrobial biological activities. ey are applicable in numerous industries, including foods, cleaning products, pharmacology, cosmetics, pesticides, textiles, fungicides on different organic surfaces, medicine, and oil and gas fields as essential biotechnology products [7, 79]. e growing interest in biosurfactants is because of their low environmental impacts, low toxicity, and biodegradability [80]. e global market for biosurfactants reached 1.5 billion USD until 2019, which is assumed to experience over a 5.5% CAGR by 2026, of which over half of it belongs to Europe [7]
Surfactants, gases, alcohols Acids, surfactants Acids, surfactants Acids, gases e microbial formulation consists of four microorganisms (NIPER Bac 1) that have been injected into four wells of the Delaware–Childers field in Oklahoma, producing primarily surfactants, alcohols, and acids, followed by regular injections of molasses used as a nutrient [99]
Summary
Received 23 July 2021; Revised 9 August 2021; Accepted 19 August 2021; Published 31 August 2021. Among all enhanced oil recovery (EOR) methods, surfactant injection is a well-known technique that reduces the interfacial tension (IFT) between oil and water and increases oil production. To demonstrate the effect of capillary forces, the nondimensional capillary number has been considered as the ratio of fluid viscosity (μ) to velocity (V), IFT (σ) between oil and water, and contact angle (θ) [46,47,48] As this ratio increases by four or five orders in the magnitude of an EOR process, the residual oil volume will reduce, which requires either an IFT decline or adjusting the contact angles for a moderate wettability, which is nearly 90 degree of interphase (θ) [46, 48]. The MEOR methods continue to gain attention because of their improved applicability, environmental friendly nature, and competitive prices [21, 56,57,58]. e existence of various microorganisms with different metabolite productions and growing properties affects the used recovery method. ere are three feasible mechanisms to use biosurfactants in the MEOR processes: Field Development Plan
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