Mechanistic study on silica nanoparticles-assisted guar gum polymer flooding for enhanced oil recovery in sandstone reservoirs

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2020-08, Vol.598, p.124833, Article 124833
• Main Authors: Bera, Achinta, Shah, Subhash, Shah, Maunish, Agarwal, Jatin, Vij, Rakesh Kumar
• Format: Article
• Language: English
• Subjects: Enhanced oil recovery; Guar gum; Imbibition; Phase behaviour; Polymer flooding; Silica nanoparticles
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2020.124833

[Display omitted] •Viscosities of guar gum with and without silica nanoparticles are studied.•Imbibition experiments are carried out to obtained spontaneous oil recovery.•Contact angle measurements are performed for wettability alteration of sandstone.•Phase behaviors of crude oil-silica nanoparticles-guar gum solutions are conducted.•Core displacement study is performed for EOR performance evaluation. Nanoparticles-assisted polymer flooding has attracted the attention of researchers for its enhanced rheological properties and stability of the chemical slugs. The present work deals with the rheological properties of guar gum with and without silica nanoparticles in the temperature range from 25 °C to 75 °C. It is found that the viscosity of guar gum solution increases significantly with increasing concentration of silica nanoparticles. Imbibition experiments were performed with waxy crude oil-saturated sandstone cores using 2000 ppm brine, 4000 ppm guar gum solution, 0.2 wt% silica nanoparticles in distilled water, and 4000 ppm guar gum containing 0.2 wt% silica nanoparticles as test fluids for understanding the mechanism of wettability alteration in the presence of silica nanoparticles and guar gum. Mixture of 0.2 wt% silica nanoparticles and 4000 ppm guar gum shows higher oil recovery (∼36 % original oil-in-place) compared to other test solutions in imbibition experiments. Contact angles between crude oil and sandstone rock were measured in presence of 2000 ppm brine, 0.025 wt% silica nanoparticles in water, and guar gum (2000 ppm)-silica nanoparticles (0.025 wt%) mixture. Guar gum containing silica nanoparticles are effective in changing the contact angle towards water-wet state (Contact angle ∼115°) from oil-wet state (contact angle ∼72°). No significant phase change is observed during the phase behavior experiment except for light emulsion formation. Finally, core flooding experiments were conducted with guar gum, silica nanoparticles solution, and mixture of silica nanoparticles and guar gum for additional oil recovery to verify the effectiveness of the chemical slugs. Results showed that the addition of silica nanoparticles to guar gum solution improves the effectiveness of guar gum polymer by recovering 44.3 % of original oil-in-place. A comparative study was also conducted to show the performance of silica nanoparticles-assisted guar gum solution for additional oil recovery. Most of the research works have focused on the application of silica nano