Adsorption/Desorption of Sulfonates by Reservoir Rock Minerals in Solutions of Varying Sulfonate Concentrations

Publisher Website
Google Scholar
Abstract
In micellar flooding, reservoir rocks are exposed to surfactant solutions of varying concentrations as the surfactant slug advances through the reservoir. Therefore, the attachment and detachment of sulfonates with rocks that are already exposed to surfactant solutions of higher or lower concentrations is of major interest. In this study, the abstraction behavior of purified Na-dodecylbenzene-sulfonate on Na-kaolinite by stepwise increase in surfactant concentration is determined. Deabstraction* occurring after reductions in surfactant concentrations at various stages also is determined. Most importantly, the results of incremental abstraction, individual abstraction, and deabstraction showed the system to exhibit hysteresis or memory effects. Also, abstractions obtained at various pH values and during stepwise changes in pH exhibited marked differences. The deabstraction isotherms showed the presence of maximum in certain cases, indicating the occurrence of maximum on the abstraction isotherms to be a real phenomenon. Possible reasons for the hysteresis are considered, and the practical implications of these memory effects on micellar flooding and depletion experiments using cores are discussed.