Al2O3–Cetyltrimethylammonium Bromide Nanofluid System for Enhanced Oil Recovery in Low Permeable Carbonate Reservoir

Chemical enhanced oil recovery using nanoparticles and surfactants has attracted the attention of researchers because of its efficacy in improving oil displacement efficiency. This research aims to investigate the impact of Al2O3 nanoparticles on cetyltrimethylammonium bromide (CTAB) cationic surfactant for improving oil recovery in low-permeability carbonate reservoirs. The presence of different mineralogy and functional groups in carbonate rock was analyzed by XRD and FTIR, respectively. A conductivity test and the surface tension method detected the critical micelle concentration (CMC) of CTAB to be around 0.9 mM. The nanofluids (Al2O3-CTAB) were found to be stable for more than a week based on visual observation and the zeta potential values of above + 30 mV. The interfacial tension (IFT) between crude oil and nanofluids was reduced to 5.4–6.7 mN/m. The solid–liquid contact angles were reduced to 28–39°, indicating a favorable water-wet condition. The emulsification of crude oil using nanofluids was observed at 30 °C and at an elevated temperature of 70 °C, highlighting the potential of Al2O3-based nanofluids. Core flooding experiments, representing dynamic behavior, resulted in cumulative oil recoveries of 23.4