Evaluation of Nanosilica Morphology: Effects on Nanofluid Stability and Interaction with Carbonate Rock Surfaces

Silica nanoparticles are being studied for enhanced oil recovery (EOR) due to their ease of production and tunable characteristics. However, limited research has explored the impact of nanoparticle morphology on their effectiveness in EOR. This study investigates the synthesis and characterization of silica nanoparticles in two distinct morphologies: spherical and rod-shaped and their adsorption onto carbonate rock surfaces. Various analytical techniques, including FESEM, EDS, FTIR, TGA, BET, and XRD, were employed to characterize the nanoparticles. The study also examined the stability and zeta potential of nanofluids prepared with these nanoparticles in different salt solutions. The results revealed that rod-shaped nanoparticles exhibited greater thermal stability and higher zeta potential than spherical nanoparticles, contributing to the improved stability of the nanofluids. Additionally, the adsorption behavior of the nanoparticles on carbonate rock surfaces was assessed, with rod-shaped nanoparticles showing higher adsorption quantities compared to their spherical counterparts. The adsorption process followed pseudo-second-order kinetics and was influenced by both intraparticle and film diffusion mechanisms. The equilibrium adsorption data for silica nanoparticles was accurately described by the Langmuir isotherm model. Moreover, artificial neural networks (ANN) and least-squares support-vector machines (LSSVM) were utilized to model the adsorption behavior of nanoparticles. The high R² values indicated that these models effectively predicted nanoparticle adsorption on carbonate rock. The study also observed that rod-shaped nanoparticles caused more significant alterations in the roughness of the rock surface than spherical nanoparticles, potentially influencing oil flow in the porous medium during the EOR process.

Graphical Abstract