The use of nanoparticles is a known solution for challenges related to enhanced oil recovery (EOR) methods, and nanoparticles have good potential for changing effective mechanisms, such as wettability alteration and interfacial tension (IFT) reduction. On the basis of our last research, it was observed that using associated gas in a water alternative gas (WAG) method has a high recovery potential in comparison to other gases, such as CO 2 and N 2 , in carbonate reservoirs. In this study, zeolite−zirconia−cerium oxide nanocomposites (NCs) with an average size of 29.15 nm have been synthesized by the sol−gel method for improving water alternative associated gas tests. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer−Emmett−Teller (BET), energy-dispersive X-ray (EDX), IFT, contact angle, WAG, and nano-assisted WAG tests were designed in the presence of NCs. The XRD and EDX patterns confirmed the formation of CeO 2 and ZrO 2 nanoparticles over the formed zeolite framework. SEM images show that the zirconia−cerium particles are uniformly distributed at the surface of zeolite. Moreover, BET analysis shows that the specific surface area of the NCs is 331.67 m 2 /g as a result of introducing ZrO 2 and CeO 2 . The IFT and contact angle values of nanofluids prepared with concentrations of 25, 50, 75, 100, 125, and 150 ppm of the NCs were determined as 22 mN/m and 116°, 19.50 mN/ m and 86°, 17.30 mN/m and 70°, 12.50 mN/m and 42°, 8.60 mN/m and 36°, and 6.80 mN/m and 38°, respectively. On the basis of these values and ζ potential, viscosity, pH, and density tests in the presence of NCs, 100 ppm was selected as an optimum concentration for improving WAG tests. It was observed that considering the above factors was efficient and the recovery factor during performing NC-assisted WAG test was increased from 42.5 to 72% at a constant WAG ratio and temperature of 1:1 and 40 °C, respectively. Moreover, more instant oil and lower produced water were observed during performing a NC-assisted WAG test at an optimum concentration of 100 ppm.
