Competing Roles of Interfacial Tension and Surfactant Equivalent Weight in the Development of a Chemical Flood

Abstract

This investigation focused on developing an efficient chemical flooding process by use of dilute surfactant/polymer slugs. The competing roles of interfacial tension (1FT) and equivalent weight (EW) of the surfactant used, as well as the effect of different types of preflushes on tertiary oil recovery, were studied. Volume of residual oil recovered per gram of surfactant used was examined as a function of these variables and slug size.Tertiary oil recovery increased with an increase in the dilute surfactant slug size and buffer viscosity. However, low 1FT does not ensure high oil recovery. An increase in surfactant EW used actually can lead to a decrease in oil recovery. Tertiary oil recovery was also sensitive to preflush type. Reasons for the observed behavior are examined in relation to the surfactant properties as well as to adsorption and retention.

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

“…These factors include the surfactant types (Hayes et al, 1979), chemistry (Enedy et al, 1982;Hirasaki et al, 1983;Krumrine et al, 1982), phase behavior (Glover et al, 1979;Novosad, 1982), chemicals adsorption (Austad et al, 1997), surfactant precipitation and redissolution (Somasundaran et al, 1984), chromatographic separation of chemicals (Li et al, 2009), surfactant convection (Ramirez et al, 1980), surfactant stability (Handy et al, 1982), chemicals loss (Friedmann, 1986), dispersion (Hirasaki, 1981), surfactant systems formulation (Salager et al, 1979), wettability , reservoir rock structure and morphology (Dullien et al, 1972;Yadali Jamaloei and Kharrat, 2009;Yadali Jamaloei et al, 2011a), and reservoir heterogeneity (Ma et al, 2007). The morphology and heterogeneity of the reservoir rock play a significant role in the behavior of chemical flooding processes.…”