Reduction of fines migration by nanofluids injection: an experimental study

Abstract

Formation damage of oil reservoirs as a result of fines migration is a major reason for productivity decline. Formation fines are defined as unconfined solid particles present in the pore spaces of formations. Their migration, caused by fluid flow in the reservoir, can cause pore plugging and permeability reduction. In the last 3 decades, many studies have characterized fines and their migration effect on permeability reduction. There are many techniques in the industry to remediate the damage, especially in the near-wellbore region. Nanofluids (NFs) that contain nanoparticles (NPs) exhibit specific properties, including a high tendency for adsorption and being good candidates for injection into the nearwellbore region, because of the small nanoparticle sizes. In this paper, a packed column is used to study the use of different types of NPs to reduce fines migration in synthetic porous materials. Three types of NPs--MgO, SiO2, and Al2O3--are used here to investigate their effects on fines movement. The results indicate that fines may adhere to the matrix grains, hindering their migration, when the porous materials are soaked with NFs. Furthermore, to check the mechanisms of this remediation technique, the effect of nanoparticle concentration and fluid flow rates in the medium on fines detachment was studied. A theoretical model was used to calculate total energy of interaction for the surfaces to check experimental results, which was also validated with scanning electron microscopy (SEM) pictures for samples from synthetic cores. The results showed that addition of 0.1 wt% of MgO and SiO2 NPs reduced fines migration by 15% compared with the reference state. MgO NPs were found to be more effective, even at high fluid rates, when used at a higher concentration, as noticed in the macroscopic and microscopic results.