Chemical flooding methods are used to recover residual oil left after water flooding. Several recovery mechanisms were suggested to improve the displacement effectiveness of the trapped oil. Reducing IFT, mobility control and wettability alteration are the main recovery mechanisms during chemical flooding. Understanding which recovery mechanism that dominate during recovery process helps selecting and optimizing which chemical process to be used.
An experimental study of 4 chemical flood experiments were visualized with computed tomography (CT) in sandstone cores at room temperature. The experiments were conducted to study four different chemical flooding processes: polymer, surfactant, surfactant-polymer (SP), and alkali-surfactant-polymer (ASP). Oil recovery, and oil distribution in the core were evaluated after the chemical flood.
The experimental results obtained from the core flooding experiment shows best recovery was during ASP and SP flooding with some residual reduction in permeability caused by using polymers. The lowest recovery was obtained during surfactant flooding, which prove that IFT reduction can’t improve recovery without the aid of mobility control by polymers.