Wettability of reservoir minerals by flotation and correlation with surfactant adsorption

Minerals can undergo significant alterations in wettability upon adsorption of surfactants on them. A method that appears promising for measuring wettability is flotation using air or oil extraction. Unlike contact angle, it does not require such drastic treatments as polishing. Good correlation was obtained in the present study between wettability as determined by flotation and adsorption density. Both air flotation and adsorption exhibit maxima in the same concentration range. Zeta potential of particles measured under the same conditions, however, shows a continuous increase in its negative value with sulfonate concentration. Correlation of these data suggests that sulfonate monomers adsorb in increasing amounts below as well as above the critical micelle concentration but with a reverse orientation. There is however a decrease in measured surface excess, possibly due to such factors as precipitate redissolution and micellar exclusion. A combined approach using adsorption, wettability, zeta potential and surface tension shows promise as a valuable method for the study of mechanisms of interaction of surface active agents with minerals. INTRODUCTION.