The first study of surface modified silica nanoparticles in pressure-decreasing application

Abstract

In this study, hydrophobic silica nanoparticles were prepared by the surface modification of silica nanoparticles using dimethyldichlorosilane. Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy were employed for the characterization of the raw silica nanoparticles and modified silica nanoparticles. The results showed that methyl groups are successfully grafted on the surface of silica nanoparticles. The titration method was employed to quantitatively determine the surface hydroxyl number of silica nanoparticles, the result demonstrated that the surface hydroxyl number of silica nanoparticles significantly decreases after modification. The modified silica nanoparticles was dispersed in water using TX-100 as the dispersant and NaOH to adjust the pH. The dispersion was injected into an oil-treated artificial core, the injecting pressure of the NaCl solution (5 wt %) before and after injection was measured. The result showed that the hydrophobic silica nanoparticles exhibit a good pressure-decreasing ability. The contact angle of the slabbed core was measured, the contact angle increased from 36° to 134° after it was treated by the modified silica nanoparticle dispersion. Transmission electron microscopy was employed for the characterization of the modified silica nanoparticles. Scanning electron microscopy was employed for the characterization of the treated core; the result showed that the modified silica nanoparticles are adsorbed on the surface of the core and forms a hydrophobic layer, changing the wettability of the sand surface from water wet to oil wet, thereby decreasing the flowing pressure.

Experimental Investigation of Polymer-Coated Silica Nanoparticles for Enhanced Oil Recovery

“…The EOR application of NPs is also hampered by poor dispersibility or stability in the injection fluid (e.g., water). Nanoparticles have an immense surface free energy triggered by their ultra-small size and large surface area, which increases the tendency of the NPs to aggregate/agglomerate in solution in an attempt to gain the low energy state [23]. As the NPs approach each other, their surface functionalities at the fluid–rock interfaces are reduced.…”

“…They attributed the EOR mechanisms to the reduced oil and water IFT and the formation of wedge film between the oil and the rock surface that readily altered the wettability. The effect of surface-modified silica NPs to decrease the water injection pressure for EOR purposes was studied by Dai et al [23] and Zhao et al [28]. The authors observed that, during the injection of nanofluid, NPs adsorbed and formed layers on the rock surface, thereby crowding the water out on it and increasing the water flowing channels, thus decreasing the injection pressure.…”

Application of Magnetic and Dielectric Nanofluids for Electromagnetic-Assistance Enhanced Oil Recovery: A Review

“…Moreover, polymer/surfactant coating on the surface of the NPs was found to promote nanofluid properties which include mobility, foams, emulsion, stability, and solubility of the fluids in a porous media [59,61,63,64]. Some experiments have shown that coating silicon dioxide nanoparticles with surfactant/polymer has revealed a productive outcome for EOR [59,61,[65][66][67]. Furthermore, coating silica NP with Al 2 O 3 NP has made them appear with a higher surface area, which resulted in better recovery than with bare silica or alumina, as reported by Negin et al [34].…”

CO2/N2-Responsive Nanoparticles for Enhanced Oil Recovery During CO2 Flooding

“…Functional nanoparticles have been applied in aspects such as wettability, surfactivity, pressure decrease, and augmented injection because of the unique properties of nanoscale particles. Sharma et al (2014), Dai et al (2015), Zhang H. et al (2016), Emrani and Nasr-El-Din (2017), and Li et al (2019). In addition, the modification of the surfaces of SiO 2 nanoparticles with pH-responsive, light-responsive, and CO 2 /N 2 -responsive groups has also been reported increasingly Jiang W. et al, 2016;Yan et al, 2018).…”