Abstract

Surfactant flooding is an important technology for enhanced oil recovery. A substantial amount of remaining oil resides in reservoirs, many of these are carbonate reservoirs that have low primary and water-flood recovery as a result of poor sweep efficiency that has resulted in bypassed or unswept oil. Chemical flooding methods such as surfactant flooding have been shown to be effective in recovering this unswept oil. The basis for surfactant flood is to inject a surface-active agent (a surfactant) to reduce the interfacial tension and mobilize the residual oil saturation. Surfactants have been widely used for different purposes since the early years of the petroleum industry because of their ability for altering the interfacial behavior between two immiscible fluids in contact with each other. Interfacial phenomena have an influence on rock-fluid interactions and interactions between fluids occurring from the reservoir to distribution pipelines; therefore, surfactants can be used for several petroleum industry activities. Several laboratory experiments, pilot-scale projects, and field-scale projects all over the world have shown different results regarding surfactant applications for enhancing oil recovery. Several types of surfactants have been studied to determine high-efficacy chemical EOR formulations. Anionic and non-ionic surfactants are commonly used in sandstone reservoirs.

Keywords: Enhanced oil recovery; Surfactant flooding; Waterflooding; Interfacial tension; Anionic surfactant; Non-ionic surfactant