Abstract
Surfactant flooding is a well-known enhanced oil recovery (EOR) technique that has been used worldwide for decades. The surfactant can meaningful lower interfacial tension and change the wetting properties. Surfactant related recovery processes are of increasing interest and importance because of high oil prices and the urge to meet energy demand. The water flooding methods include chemical flooding and low-salinity water (LSW) flooding. Chemical flooding methods have been developed to recover residual oil trapped after conventional oil recovery is getting important recovery. The LSW flooding includes injecting brine with a lower content of salt or ionic strength. Water flooding improves oil recovery by displacing oil, and injection water is usually taken from the nearest available source. The injected alkali and surfactant, so that the interfacial tension between oil and water is lowered and thus residual oil can move. There is a relationship among chemical EOR efficiency and fluid viscosity, relative permeability, interfacial tension, wettability, and capillary pressure. The polymer increases the viscosity of the flooding water, reduces water mobility, and thus greatly reduces oil flow ratio so to reduce water flooding fingering, improve horizontal and microscopic pore structure reservoir heterogeneity condition, relieve channeling flow around other phenomena, and increase the flooding swept volume of water.