ABSTRACT
Petroleum is the most widely used energy source in the world. Since a significant amount of crude oil is trapped in reservoirs after conventional primary and secondary recovery, economical ‘enhanced oil recovery’ (EOR) becomes increasingly important. As the interest in environmental problems due to petroleum development is growing and environmental regulations are becoming strict, the development of environmentally friendly methods has become essential. The EOR method combining microbial technology can be an environmentally friendly and economical alternative. This chapter deals with the various mechanisms used for oil production in the ‘microbial enhanced oil recovery’ (MEOR) process. The main strategies for the application of MEOR are determined by the main substances generated from microbial activity. In particular, selective plugging by biomass/biopolymers and wettability alteration by biosurfactants are described as the main mechanisms for oil recovery. The effects of biosolvents, bioacids, and biogases are also engaged. Additionally, the degradation of hydrocarbons by microorganisms and the effect of improving oil recovery is described. This review aims to increase the understanding of how microbial technology can be applied to oil production engineering. The literature pertaining to laboratory experiments, numerical simulations, and field trials are included in the light of industrial applications.
