Chapter 7 - Surfactant Flooding

Abstract

This chapter deals with the fundamentals of surfactant flooding method of chemical oil recovery, which includes microemulsion properties, phase behavior, interfacial tension, capillary desaturation, surfactant adsorption and retention, and relative permeabilities in surfactant flooding. Anionic surfactants are most widely used in chemical enhanced oil recovery (EOR) processes because they exhibit relatively low adsorption on sandstone rocks whose surface charge is negative. Surfactant solution phase behavior is strongly affected by the salinity of the brine. The phase behavior of microemulsions is complex and depends on a number of parameters, including the types and concentrations of surfactants, cosolvents, hydrocarbons, brine salinity, temperature, and to a much lesser degree, pressure. The phase behavior of microemulsions is typically presented using a ternary diagram and empirical correlations such as Hand's rule. An experimental study of surfactant flooding in a low-permeability reservoir is also presented.