Abstract
Formation damage of the oil reservoirs because of fines migration is a major reason for productivity decline. Formation fines are defined as unconfined solid particles present in the pore spaces of the formations. Their migration because of fluids flow in the reservoir would cause pore plugging or permeability reduction. In the last three decades, many studies have been done for the characterization of fines and their migration effect on permeability reduction. There are many techniques in the industry to remediate the damage, especially near well bore regions.
Nanofluids that contain nanoparticles show specific properties such as high tendency for adsorption and good candidate for the injection into the near wellbore regions because of their very small sizes. In this paper, a packed column is utilized to study the use of different types of nanoparticles to reduce fines migration in synthetic porous materials. Three types of nanoparticles; MgO, SiO2 and Al2O3 are used here to investigate their effects on the fines movement. The results indicate that the fines could stick into the grains hindering their migration when the porous materials are already soaked with nanofluids. Besides, to check the mechanisms of this remediation technique, the effect of nanoparticle concentrations and fluid flow rates in the medium on the fines detachment was studied. A theoretical model was employed to calculate the total energy of interaction for the surfaces to check the experimental results, which was also validated by using SEM pictures for samples from the synthetic cores.
The results showed that the addition of 0.1 wt% of MgO and SiO2 nanoparticles would reduce the fines migration by 15% compared to the reference state. MgO nanoparticles were found to be more effective even at high fluid rates when it is used at higher concentration as it is noticed in the macroscopic and microscopic results.
