Stability of Silica Nanofluids at High Salinity and High Temperature

Nanoparticles have shown great potential in many sectors of the oil and gas industry, including enhanced recovery (EOR). They can be used to improve water flooding by altering wettability porous medium, reducing interfacial tension, blocking pores, or preventing asphaltene precipitation. Ensuring stability nanofluids injected into reservoirs is essential a challenge. However, high temperature favors particle collisions salinity (ionic strength) decreases electrostatic repulsion between particles. Therefore, are extremely unstable at reservoir conditions. In this paper, we investigated effects electrolytes (brine seawater) (up 80 °C) on silica nanofluids. The characterized dynamic light scattering (size), turbidity (stability), zeta (electrostatic repulsions). One solution increase compensate for loss repulsive forces due salts through increased and/or steric repulsions changing pH base fluid. At ionic strength (42 g/L NaCl seawater), 0.1 0.5 wt% basic about one day, regardless temperature. contrast, 1.5, least three weeks °C. results obtained with fluids containing divalent cations confirmed their more destabilizing effect. This study that it possible stabilize beyond month conditions just lowering near isoelectric point.