Pore-scale study of in-situ surfactant flooding with strong oil emulsification in sandstone based on X-ray microtomography

This study presented a pore-scale investigation on the dynamic displacement of oil subjected to ex-situ and in-situ surfactant flooding using X-ray microtomography. The solution was pre-prepared, whereas generated directly with chemical reaction inside porous media. results showed that removal from pore spaces relied combination piston-like, pore-body filling weak emulsification mechanism in system, system dominated by strong process. threshold capillary pressure decreased significantly owing interfacial tension reduction wettability alteration, which enhanced cluster mobilization. Therefore, produced highest recovery efficiency 86.9% compared water flooding. emulsifying ability evaluated through size distributions their evolution. networks or branches disappeared emulsified into small ganglia singlets, thereby leading significant decrease average equivalent diameter. Finally, attributed quick precise aggregation at oil–water interface induced blebbing, case slow transport relying advection diffusion flow mainstream.