Mitigation of fine particles migration in deep bed filters treated by a nanofluid slug: An experimental study

Fine particles migration in porous media (deep bed filters) is one of the main reasons causing formation damage especially during any well stimulation techniques or enhanced oil recovery (EOR) processes. It has been explained by lifting of in-situ fine particles present in the medium, their motion with the flow, and finally their capture at some pore throats. Attachment of particles to the rock surface during EOR agent injection into the reservoir can be a very promising remedy for the aforementioned challenge. In this experimental study, the role of nanoparticlestreated medium as an adsorbent of suspended particles has been investigated. Different concentrations of MgO and SiO₂ nanoparticles were utilized to treat the synthetic porous media. In several core flooding tests, a stable suspension was injected into the already nanoparticles-treated medium and particles concentration of effluents was measured by turbidity analysis. In order to quantify the effect of nanoparticles to alter the medium surface characteristics, zeta potential analysis and dynamic light scattering methods have been applied. The results indicated that the presence of nanoparticles on the medium surface alters the zeta potential of the rock which in turn, results in critically reduction of particles concentration in the effluent samples compared with the non-treated media. It was found that treating with 0.03 wt% of MgO nanoparticles is the best scenario among the tests performed in this study. This finding was confirmed by DLVO theory by which the total energy of interactions existing between a particle and the rock surface was calculated.