hydrophobicity of sandstone rock surface by nanofluids

Water flooding is an effective method to increase oil recovery which its performance highly dependes rock on wettability# in this study, effect of a new nanofluid on wettability alteration of sandstone reservoir is investigated# oil wet thin sections were aged in different nanofluid concentrations at 25 ℃ and 80 ℃# effect of nanofluid on wettability alteration was studied by measuring contact angle and surface energy# results show wettability altered from strongly liquid-wet to strongly gas-wet after adsorption of nanofluid on rock# the optimum concentration is 0#05 wt# % that changes contact angle from 78#41 to 125#85 at 25 ℃ and from 78#41 to 129#34 at 80 ℃ and decreases surface free energy from 1 to 0#34 (mn/m) at 25℃ and from 1 to 0#304 (mn/m) at 80℃ due to adsorption of nanoparticles on rock surface#