Surfactant (Sodium dodecyl sulphate) Coated Silica (SiO2) Nanoparticles for Enhanced Oil Recovery: An Optimized Approach

Increasing demand of hydrocarbons has prompted new strategies of recovery by application of nanoparticle-surfactant flooding in Chemical Enhanced Oil Recovery (CEOR). Some mechanisms involved in improving oil mobility are alteration of rock wettability and reduction in interfacial tension between the oil and water. In this work, silica (SiO2) nanoparticles (NPs) were synthesized, characterized and their effect on wettability alteration and interfacial tension (IFT) between the oil and SiO2 NPs dispersed in Sodium dodecyl sulphate (SDS) solutions was determined. Experiments on displacement of oil by flooding with brine and NPs dispersed in SDS solution were investigated in a micro glass model. X-ray Diffraction (XRD) pattern and Scanning Electron Microscopy (SEM) confirmed the mineral structure and platy polycrystallite morphologies that gave an estimated particle size of 88 nm using Scherrer’s formula. Fourier Transform Infrared Spectroscopy (FTIR) showed characteristic symmetric and asymmetric stretching vibrations. The wettability alteration and IFT measured showed changes in wettability from water-wet towards a more water-wet condition and a decrease in IFT respectively as the SDS concentration increased. The optimum oil recovery of 67.45% was obtained at 2.08 mM SDS when SDS concentrations were varied (2.08, 6.25, 8.33, 10.42 and 14.58 mM) at constant SiO2 NPs (0.1% wt.). Having obtained the optimum oil volume from OOIP at 2.08 mM SDS, SiO2 NPs concentration was varied (0.05, 0.1, 0.15, 0.2 and 0.25% wt.) at constant SDS concentration (2.08 mM). This optimized approach gave an excellent total oil recovery of 78.36% at 0.2% wt. SiO2NPs. It is therefore recommended that 0.2% wt. SiO2NPs with 2.08 mM SDS be applied in oil recovery.