Salinity, pH, and Surfactant Concentration Effects on CO2-Foam

Abstract

Abstract The influence of a number of parameters on CO2-foam stability and surfactant adsorption at reservoir conditions are determined. In this work changes of pH from 1 to 12, salinity from 0 to 25 wt%, and surfactant concentration from 0 to 1 wt % were tested for foam stability in a bubble chamber and for adsorption in a static adsorption apparatus using pure kaolinite powder. The mechanisms by which pH and salinity influence CO2-foam behavior are also discussed in the paper. Stability of CO2-foam is surfactant concentration-dependent. The foam was stable under all tested pH and salinities at concentrations both below and above the critical micelle concentration (CMC) except at the lowest concentration tested (0.005 wt%). The adsorption of surfactant onto kaolinite increased with salinity for both NaCl and CaCl2 with the divalent salt system inducing a higher adsorption onto the kaolinite.