Synergistic Oil Recovery Effect of Nanoparticles and Surfactants

Due to being environmentally friendly, nanoparticles have recently attracted lots of attention for enhanced oil recovery applications. However, the main challenge in using nanoparticles is that they must maintain colloidal stability under harsh reservoir conditions. This research focuses on assessing surface-modified fumed and colloidal nano silicas on surfactants to enhance oil recovery, with a special focus on wettability alteration, colloidal stability in brine at high temperature, interfacial tension (IFT), and emulsification characteristics. Contact angle measurements were used to study the wettability alteration of core chips using the captive bubble method. Interfacial tension was measured by using the spinning drop method. Recovering of liquid hydrocarbons was tested by spontaneous imbibition experiments. The emulsion tendency was studied visualizing the phase behavior of the oil and aqueous solution after shaking the sample for 30 seconds. The surface of the silica nanoparticles was modified with silane to enhance the colloidal stability of nanofluids. Surface-modified nano silicas did not change the core wettability and remained oil wet while the surfactant altered to intermediate wet. However, the mixture of nano silica and surfactant changed the core wettability to water wet, exhibited a lower IFT than individual components, and produced 60% oil recovery as compared to 20% for surfactant alone and 11% for particles alone, suggesting the significant synergistic mixture. Colloidal stability was achieved and then enhanced when blended with a small amount of alum. Emulsions were resolved after 20 minutes when treated with the mixture of nano silica and surfactant compared to stable emulsion for the untreated. Surface-modified nano silicas, in general, can deliver significant benefits, including reduced chemical usage, optimized logistics, and lower CO2 emissions.