Asphaltene stability during heptane injection in a glass micromodel in the presence of Co₃O₄ nanoparticles

Severe challenges and difficulties in oil production may arise from asphaltene precipitation and deposition in porous media and upstream facilities. The investigation for a proper solution for such detrimental damages is indispensable for the oil industry. Nanoparticles, due to their unique properties of high degree of dispersibility and high adsorption affinity, may potentially be useful for hampering the asphaltene related problems to some extent. In this study, by the use of glass micromodels, the utilization of Co₃O₄ nanoparticles to stem asphaltene precipitation has been investigated. These nanoparticles were dispersed in synthetic solutions comprising of toluene, n-heptane and asphaltenes as well as crude oil. The prepared solutions were then subjected to n-heptane injection as asphaltene precipitator. The amount and extent of asphaltene precipitation and deposition in micromodels was then measured and analyzed. The results showed that Co₃O₄ nanoparticles positively affect asphaltene stability in both crude oil and synthetic solutions. However, it was found that once these nanoparticles adhere to glass surface, then intense asphaltene precipitation and deposition would take place. The impacts of nanoparticle concentration were also discerned through experiments for 0.01, 0.05 and 0.1 wt% concentrations of nanoparticles. It was obtained that generally, higher concentration of nanoparticles would reduce asphaltene precipitation intensity. However, due to very little difference between the efficiency of solutions containing 0.05 and 0.1 wt% in terms of increasing asphaltene stability, 0.05 wt% of dispersed nanoparticles was found to be the optimum concentration for preventing asphaltene precipitation and deposition. This study, for the first time, provides a micro visual study in order to observe the impacts of nanoparticles on the stability of asphaltene in crude oil and synthetic oil samples in a uniformly patterned glass micromodel.