Evaluation of Polymer Wettability Alteration and Adsorption of Modified Silica Nanoparticles for Enhanced Oil Recovery

The change in the wetting of rock from hydrophobic to hydrophilic is named "wettability alteration". This is an important factor for enhanced oil recovery (EOR). Because of their unique properties, nanoparticles have attracted much attention for enhanced oil recovery. Despite promising results, the main challenges of using nanoparticles are related to colloidal stability and poor absorption of nanofluids under harsh conditions. In recent years, polymer-grafted nanoparticles have been considered as emerging materials for enhanced oil recovery.

In this study, wettability and absorption of polymer-grafted nanoparticles including silica nanoparticles modified by polyethylene glycol methyl ether (mean molecular weight 2000), silica nanoparticles modified by two polymers: polyethylene glycol methyl ether (mean molecular weights 2000 and 5000) and propyl chains are investigated. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to investigate the chemical bonding and polymer content on the silica surface. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), water contact angle measurement, and UV-Vis spectroscopy were also used to study morphology, material composition, wettability, and absorption of the substrate, respectively.

Best performance for silica nanoparticles modified by polyethylene glycol methyl ether (average molecular weight 5000) and propyl chains at 1000 ppm concentration and salinity range 20000-40000 ppm was obtained. This study shows that silica nanoparticles bonded to different polymers can be considered as an effective and novel approach for enhanced oil recovery.