Electrostatic characterization of -NH+-brine-kaolinite system: Implications for low salinity waterflooding in sandstone reservoirs

摘要

Oil-Brine-Rock interaction appears to be an important physiochemical process, which governs multiphase flow and residual oil saturation during low salinity waterflooding in sandstone reservoirs. While it appears that electrostatic adhesion of oil polar components on clay edges and basal planes regulates oil-brine-rock interactions, relative contribution of adhesion on edge and basal planes remains unclear, thus presenting a substantial impediment to model and predict the low salinity effect. We thus coupled PEST and PHREEQC to model the quinoline adhesion against RezaeiDoust et al.,'s (Energy Fuels 2011, 25, 2151-2162) kaolinite-quinoline adsorption experimental data. We matched the experimental data by examining the adsorption capacity of quinoline on kaolinite basal and edges planes simultaneously. Our new calibrated model shows that basal adsorption ( > Na + BaseH(+) = > BaseH + Na+) dominates quinoline adsorption at low pH (pH = 5). Rather, edge adsorption controls adsorption mechanism at high pH (pH = 8). Furthermore, the model shows that salinity plays a minor role in adsorption at a controlled pH system. Our new model quantifies the relative contribution of basal and edge planes on basic component adhesion thus wettability at different pH and salinity, providing insights and new geochemical data to existing geochemical database, thereby better model and predict the wettability alteration during low salinity waterflooding.