Enhanced oil recovery from sandstone reservoir using cationic hyperbranched polyamidoamine dendrimer surfactant flooding under real reservoir conditions

Abstract

Abstract This study investigates the application of a synthesized cationic hyperbranched polyamidoamine (PAMAM) dendrimer surfactant (G2-C12) as a novel chemical agent for enhanced oil recovery (EOR) in sandstone reservoirs under realistic high-salinity and high-temperature conditions. The dendrimer was synthesized via a divergent approach involving Michael addition, amidation, and quaternization, yielding a structurally defined amphiphilic macromolecule. Its performance was evaluated through interfacial tension (IFT) measurements, salinity-dependent behavior, wettability alteration tests, and core flooding experiments. The surfactant reduced IFT from 27 mN/m to 5 mN/m at 2000 ppm, which was identified as the critical micelle concentration (CMC). Contact angle measurements confirmed a significant shift from oil-wet to strongly water-wet conditions (10.87°–34.57°). Additional salinity tests established the optimal brine strength, while core flooding results demonstrated an incremental oil recovery of 29.09% at reservoir-representative conditions. These findings underscore the dendrimer’s dual-function mechanism, operational stability, and strong potential as a high-performance EOR surfactant under challenging field environments.