Excessive water production from matured oil fields has become a major challenge in extracting hydrocarbons economically. Unfavorable mobility ratio and heterogeneous reservoir formation has been identified as one of the root causes for this challenge. The injected water tends to flow in regions with high permeability and thus leave behind unswept hydrocarbons in regions with low permeability. One of the methods currently being tested is the use of sodium silicate-nanoparticle mixture which acting as a diverting agent. The main challenge in using nanoparticles is their stability in tough conditions, namely high temperature, high pressure, and intermediate to high salinity. The present study aims to focus on the investigation of nanoparticles dispersion stability in sodium silicate system by measuring the zeta potential of the mixture solution. The influences of various parameters like stabilizer concentration and its molecular weight, and stability versus time on the suspension stability are thoroughly evaluated. Besides, temperature exposure effect (aging effect) on the dispersion stability was also investigated. The results have shown that dispersions of nano-silica and nano-zinc oxide in sodium silicate solution were stable with the present of stabilizer. The low molecular weight (1500 MW) polyethylene glycol and its concentration was found positively influencing the stability of nano-silica and nano-zinc oxide in sodium silicate solution. Besides, the colloidal nanoparticle stability in a specific time scale has decreased over time whereas nano-zinc oxide performed better than nano-silica. It was also noted that both nanoparticles dispersion stability could not be maintained for high temperature exposure for longer period. © 2019 Author(s).