Numerical modeling of asphaltene deposition in CO2-flooded porous media

CO2 flooding disrupts asphaltene balance, causing deposition and reservoir damage. Most models lack core verification, resulting in inaccurate predictions of asphaltene deposition and reservoir performance. The Discrete Phase Model (DPM) of Volume model for characterizing asphaltene deposition during CO2 flooding was established by coupling Volume of Fluid with DPM, which simulates the complex interaction between CO2-flooded crude oil and asphaltene flow deposition dynamics. Key factors such as CO2 mole fraction, displacement velocity, crude oil viscosity, asphaltene density, and particle size on asphaltene deposition, as well as the impact on reservoir porosity and permeability degradation, were comprehensively examined. The findings show that increasing CO2 mole fraction from 0.2 to 1 enhances asphaltene deposition rate by 53.6% and damages porosity and permeability by factors of 2.4 and 5.78, respectively. Raising CO2 injection velocity rises from 0.006 to 0.016 m/s reduces the deposition rate by 17.97%, the porosity damage factor drops from 1.981 to 1.075 and the permeability damage factor decreases from 3.926 to 1.556. Higher crude oil viscosity significantly reduces both deposition rate and related damage, while increasing particle density and diameter correlate with greater deposition and damage rates. Asphaltene particles accumulate within the throats of porous media as dispersed particulates, while they densely pack within the pores. Gray correlation analysis reveals that CO2 mole fraction exhibits the highest relationship with both the rate of asphaltene particle deposition and the extent of pore permeability impairment. This study enhances understanding of asphaltene deposition dynamics and reservoir damage mechanisms in CO2-flooded.