Numerical Simulation of Asphaltene Precipitation and Deposition during Natural Gas and CO2 Injection

Asphaltene deposition is a significant problem during gas injection processes, as it can block the porous medium, the wellbore, and the involved facilities, significantly impacting reservoir productivity and ultimate oil recovery. Only a few studies have investigated the numerical modeling of this potential effect in porous media. This study focuses on asphaltene deposition due to natural gas and CO2 injection. Predictions of the effect of gas injection on asphaltene deposition behavior have been made using a 3D numerical simulation model. The results indicate that the injection of natural gas exacerbates asphaltene deposition, leading to a significant reduction in permeability near the injection well and throughout the reservoir. This reduction in permeability strongly affects the ability of gas to flow through the reservoir, resulting in an improvement of the displacement front. The displacement efficiency of the injection gas process increases by up to 1.40% when gas is injected at 5500 psi, compared to the scenario where the asphaltene model is not considered. CO2 injection leads to a miscible process with crude oil, extracting light and intermediate components, which intensifies asphaltene precipitation and increases the viscosity of the remaining crude oil, ultimately reducing the recovery rate.