Dynamic Adsorption and Oil Recovery of Nanosilica on Carbonate Rock

Numerous studies have investigated the use of nanosilica particles for enhanced oil recovery (EOR). Many of these studies focused on experiments involving LHP (lipophobic and hydrophilic polysilicones) and HLP (hydrophobic and lipophilic polysilicones) in water-wet sandstones and oil-wet carbonate rocks. This paper's gap investigates comparing LHP and HLP nanosilica particles in enhancing oil recovery in water-wet and neutral-wet carbonate rocks. Additionally, the effects of LHP and HLP adsorption during injection and their influence on oil recovery have not yet been extensively investigated. This study used Sumatran crude oil from Indonesia, and to support the objectives of this study, several analyses were conducted, including measurements of rock wettability, interfacial tension, fluid stability, zeta potential, UV-vis spectrophotometric adsorption, and coreflood injection as the main experiment under different scenarios. The findings demonstrate that the oil recovery enhancement is influenced by the type of nanosilica used. Specifically, LHP nanosilica exhibited higher oil recovery in neutral-wet carbonate rocks, about 9.78-44.44%, while HLP nanosilica showed better performance in water-wet carbonate rocks in the range of 4.11-41.01% in different injection scenarios. Moreover, a directly proportional relationship was observed between the adsorption of LHP and HLP nanosilica on the rock and fluid and oil recovery, where increased adsorption corresponded to higher oil recovery for each injection scenario with the respective type of nanosilica about 0.06-0.15 mg/g. These results provide valuable insights into selecting the appropriate nanosilica and initial wettability conditions in EOR applications.