vUsing of nanoparticles and altering mechanisms such as wettability alteration (CA) and interfacial tension (IFT) reduction in carbonate reservoirs are common methods used to recover more oil (nanoparticles-assisted EOR) from these reservoirs. ZnO/SiO2/Xanthan as a new nanocomposites were introduced at reservoir conditions and different salinity, and results compared with commercial SiO2 nanoparticles in this study. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET) tests were used for observing morphology and the crystal structure of reservoir. Then, nanocomposites and SiO2 nanocomposites at 0.05 wt. % were used for seeing IFT and CA parameters at reservoir conditions and different salinity. It was found that nanocomposites have better results during IFT, and CA tests in compared to SiO2 nanoparticles, and nanocomposites selected for surveying the salinity effect in the presence of nanocomposites on low permeability carbonate porous media with imbibition tests. CA (2SW, 10 SW) decreased from (86 ̊, 80 ̊) to (79 ̊, 78 ̊) and (75 ̊, 74 ̊) in the presence of nanocomposites and SiO2, respectively at 60 °C and 1800 Psi. Two other important factors were change effectively in the presence of nanocomposites were IFT and stability tests. Nanocomposites show stable behavior at different salinity (ZP at 10 SW: 31.37, ZP at 2 SW: -28.00), and IFT decreased in the presence of 2SW and 10 SW (higher in 2 SW). Finally, recovery factor was increased at both 2 SW and 10 SW in the presence of nanocomposites and reservoir conditions (2SW: 25.1 %, 10 SW: 34.1 %).
