Effect of Nano-Silica Synthesized from Rice Husk on Low Salinity Water Flooding

Abstract

Abstract Water flooding is acknowledged as an environmentally friendly and economically feasible approach in Enhanced Oil Recovery (EOR) and remains a subject of fascination for researchers due to its intricate microscopic mechanisms and challenges. This research explores the microscopic effects of rice husk-derived nano-silica on oil recovery in both low salinity water flooding (LSWF) and high salinity water flooding (HSWF) methods. These methods are considered environmentally sustainable and economically viable in Enhanced Oil Recovery (EOR). Initial investigations involved zeta potential and contact angle measurements to assess surface wettability under varying pH and saline concentrations in n-decane environments. The nano-silica, synthesized through thermal and chemical treatments of rice husk, exhibited an amorphous structure with height and width dimensions of 50 nm. Contact angle measurements on muscovite surfaces treated with stearic acid showed that nano-silica positively influences EOR efficiency in both LSWF and HSWF scenarios. Particularly, nano-silica significantly reduced the final contact angle, with the most notable effect observed at pH 6. In LSWF with nano-silica at this pH, the final contact angle decreased by 42% in n-decane, while in HSWF, it decreased by 55%. Moreover, a lower pH resulted in a faster rate of contact angle change, with pH 2 exhibiting the highest rate. These findings contribute valuable insights for advancing water flooding, offering practical implications for the industry by improving oil recovery efficiency and minimizing environmental impact.