The world heavily relies on petroleum as a primary energy source, yet a significant portion of the oil-in-place remains inaccessible to conventional recovery methods. This chapter provides succinct on the application of both chemical and microbial methods to enhance the production of residual crude oil from wells through tertiary recovery methods. Further, it also reports various types of surfactants and biosurfactants used in the petroleum sector, including their classification, characterisation and inherent features. The main emphasis of the present chapter is factors affecting sweep efficiency, interfacial tension and contact angle, which are discussed in relevant sections. The study aims to gather data on fundamental chemical and microbial-enhanced oil recovery aspects and their limitations. Furthermore, the role and nature of biosurfactants are deliberated. This comprehensive review aims to provide a valuable resource for researchers, engineers and industry professionals focused on enhancing the efficiency and sustainability of oil recovery in the energy sector.