Geochemical-Based Coupled Modeling Approach for Low Salinity Surfactant Polymer (LSSP) Injection: Impact of Temperature, Salinity, Surfactant Concentration, and Sulfate Spiking on Surfactant Adsorption

Abstract

Advance chemical oil recovery techniques such as low salinity surfactant polymer (LSSP) flooding possibility of increasing oil recovery has been demonstrated by a number of laboratory experiments. In these and related chemical EOR techniques, sodium hydroxide is used to raise the injection solution's pH and decrease anionic surfactant adsorption. However, more precise surfactant adsorption level estimations is needed in the context of low salinity surfactant polymer (LSSP) flooding. Thus, an integrated geochemical framework is developed to understanding of the geochemical interactions between rocks, oil, and brine, as well as surfactants and polymers. Currently, geochemical reactions involving rock-brine, oil-brine, surfactant-brine, and oil-surfactant are considered by surface complexation models (SCM). Here, we take it a step further and apply the surface complexation geochemical reactions for polymers and coupling them for the first time for geochemical modeling of LSSP flooding. We compared our model with four distinct experimental data sets from the literature and investigated different parameters affecting surfactant adsorption during LSSP flooding. The adsorption of surfactant and effluent concentration was determined accurately by the coupling of polymer-based surface complexation geochemical reactions. Furthermore, we carried out a thorough simulation analysis, and the results show that raising the chemical flood's temperature decreases surfactant adsorption while raising its concentration in the effluent. Additionally, our analysis shows that because there are stronger repulsive forces between the adsorbed species and the rock surface, surfactant adsorption on the rock surface is reduced when the overall salinity of the water is reduced. Moreover, increasing the concentration of surfactant in the chemical flood causes the concentration of surfactant in the effluent to rise along with a notable increase in surfactant adsorption. We also observed that sulfate spiking has a noteworthy impact, as surfactant adsorption is decreased by an increase in sulfate concentration. Notably, injecting diluted water produced the lowest levels of surfactant adsorption. It is crucial to note that this work is the first to investigate a novel formulation of surface complexation modeling that takes into consideration the influence of interactions between polymer, surfactant, oil, brine, and rock on the adsorption properties of surfactants.