Remedial Effects of Metal Oxide Nanoparticles to Treat Suspension Transport in Saturated Porous Media

摘要

Hydrocarbon production decline as a result of formation damage caused by fines migration has been widely observed in laboratory corefloods and natural flows in porous media. Permeability impairment due to fines migration is explained by different capture mechanisms of already released particles at some pore sites. Preventing detachment of in-situ particles from the rock surface during enhanced oil recovery (EOR) agent injection into the porous media has been reported recently. In this experimental study, the effect of five types of metal oxide nanoparticles; γ-Al2O3, ZnO, CuO, MgO and SiO2 to adsorb the fine particles existing in the flowing suspension has been investigated. In each test, the prepared nanofluid was utilized to saturate the synthetic porous media. During core flooding tests in which suspension was injected into the treated porous media, effluent samples at different pore volumes were obtained and their fine concentrations were measured by Turbidimeter apparatus. In this study, we present quantification methods of zeta potential analysis and dynamic light scattering (DLS) in order to compare the remedial effect of different nanoparticles. It was found that the presence of nanoparticles on the rock surface changes the surface charge of the porous media and results in zeta potential alteration of the rock surface. Therefore, treated porous media tend to collect the fine particles from the flowing suspension and according to the turbidity analysis, there is a critically reduction of fine concentration in the effluent samples compared with the non-treated media. It was found that treating with γ-Al2O3 and ZnO nanoparticles are the best scenarios among the tests performed in this study. Scanning electron microscopic (SEM) images qualitatively proved the attachment of fines to the rock surface treated by nanoparticles. These findings were confirmed by DLVO theory to calculate total energy of interactions existing between a particle and the rock surface.