In Situ Nanosilica-Based Fluid for Water Shutoff: A Kinetic Study

This study introduces advanced nanosilica as a sustainable and economical solution for water shutoff applications. We investigated the reaction kinetics of a nanofluidic in situ gel system, namely, nanosilica, that can be deployed in a targeted zone like vuggs, natural or induced fractures, and a high permeability streak. To systematically assess this nano-based fluid, the chemical properties prior to, during, and following the gelation reaction at a specific reservoir condition were examined to accurately predict the gelation time (GT) and avoid premature gelation during fluid injection. This study evaluated the gelation reaction of the nanosilica system by monitoring viscosity development using a high-pressure/high-temperature (HPHT) viscometer. This study investigated the effect of the temperature and activator concentration on GT. The results of the experiments led to the development of a robust kinetic model, which was validated by lab experiments. The study revealed that the GT is exponentially related to the temperature and activator concentration. The reaction order of nanosilica was higher than that of the activator. The developed gelation kinetic mode is given as $GT=\frac{C_{Ai}}{6.3297\exp (-\frac{126,430}{RT})C_N^{23.44}{C}_A^{16.18}}$. The model has a significant impact on optimizing and designing nanosilica treatment prior to field execution based on the predicted GT at specific bottomhole temperatures.