Application of silica nanofluid to control initiation of fines migration

Abstract: Core flooding experiment was carried out through SiO2 nanofluid, which was used to change the surface properties of the pore walls, improve the attractive force between fines and pores walls against the hydrodynamic repulsive force in order to increase the critical velocity and injection rate and control fines migration. Injecting SiO2 nanoparticles has the great potential to control fines migration during water injection, which means that the higher fluid production/injection rate can be designed. The flooding test results indicated that SiO2 nanofluid with mass fraction of 0.1% showed the best performance and reduced the migration of fines by 80%. Increasing the salinity of the injection fluid had no effect on the nanofluid performance in controlling the fines migration. Measurement of the Zeta potential of the core surface showed that the SiO2 nanofluid did not change the Zeta potential of the pore walls due to the negative charge of SiO2 nanoparticles. AFM (Atomic Force Microscope) analysis proved that the SiO2 nanofluid increased the roughness of the pore walls was the main mechanism controlling fines migration and more hydrodynamic force was needed for fines movement in the porous medium. Also, for all the experiments, the total applied forces and torques on the fine particles were calculated. The theoretical results were in good agreement with the experiments, which proved that the fines migrated by rolling mechanism mainly. Key words: fine migration, critical velocity, SiO2 nanoparticle, surface roughnes