Synthesis of silica nanoparticles with different morphologies and their effects on enhanced oil recovery

Abstract

Silica nanoparticles (NPs) have been synthesized by titration of potassium silicate with hydrochloric acid, characterized and the effects of process parameters on size and morphology have been investigated. The size of the NPs decreased with increasing temperature and potassium silicate concentration. Central composite design (CCD) was applied to systematically determine the most significant factors affecting the particle size and optimize the experimental conditions to achieve minimum particle size. The optimal experimental conditions were obtained at hydrochloric acid concentration of 0.6 M, potassium silicate concentration of 11.85 wt% and temperature of 63.3 °C. SEM images proved that the pH and temperature shifted the NPs to non-spherical morphologies. To identify the effect of NPs morphology on oil recovery, some micromodel tests were conducted using the synthesized NPs with different shapes (0.1 wt%). The results showed that spherical NPs with high uniformity were the most effective in interfacial tension (IFT) reduction (3.66 mN/m) and wettability alteration to more water wet state (47.1% reduction of contact angle) compared to other applied NPs, resulted in highest oil recovery (32%). This was attributed to more homogeneity and better dispersion of spherical NPs compared to others.

Experimental evaluation of oil recovery mechanism using a variety of surface-modified silica nanoparticles: Role of in-situ surface-modification in oil-wet system

“…Meanwhile, as seen in the wide-angle XRD pattern in Fig 9 (the insert image), a single broad peak was observed at 2θ ≈ 23° which suggests that all the samples of PEG-silica nanoparticles are amorphous and non-crystal structures were formed during the reaction phase. These findings are in accoradance with the previous studies [ 58 , 59 ].…”

Spontaneous Imbibition Oil Recovery by Natural Surfactant/Nanofluid: An Experimental and Theoretical Study

“…It has been proven that nanoparticles can penetrate the micron-sized pores and throats of the reservoir rocks and improve oil recovery afterward [ 39 , 40 ]. The nanoparticles can unfavorably affect fluid flow in the porous media if the nanofluid concentration exceeds a certain amount due to entrapment [ 41 , 42 ].…”