%0 Journal Article %A Xu, Shijing %A Wu, Jiazhong %A Lv, Weifeng %A Wang, Jingyao %A Liu, Qingjie %D 2016 %I Begell House %K enhanced oil recovery (EOR), ion tuning waterflooding, zeta potential, atomic force microscopy (AFM) %N 4 %P 373-376 %R 10.1615/SpecialTopicsRevPorousMedia.2016017437 %T EXPERIMENTAL STUDY ON THE WETTABILITY ALTERATION MECHANISM OF ION TUNING WATERFLOODING %U https://www.dl.begellhouse.com/journals/3d21681c18f5b5e7,0f3d3b53575bdecc,3a27757e6dd638d0.html %V 7 %X Ion tuning waterflooding has been a promising technology used in enhanced oil recovery (EOR) in recent years. The general agreement among researchers is that ion tuning waterflooding causes reservoirs to become more water-wet. Although different mechanisms have been proposed to explain wettability alterations, the primary mechanisms are still uncertain. Therefore, this paper investigates this major mechanism of wettability alteration and shows how it is involved in the EOR process. In the present study, divalent ions were introduced into liquid films and the ion tuning effects at the molecular level were revealed. Atomic force microscopy and zeta potential measurements were used to analyze the influencing factors of disjoining pressure as well as the zeta potential at the oil/brine/rock interfaces. It has been shown that decreasing the divalent cations and salinity makes the electrical charges at both the oil/brine and brine/rock interfaces become strongly negative, which results in elevation of the repulsive forces between oil and rock. As a result, the rock becomes more water-wet. In conclusion, the double-layer expansion caused by the highly negative zeta potential as a result of lower salinity plays a major role in recovering additional oil. %8 2017-04-24