چكيده به لاتين
Asphaltene is one of the heaviest components of crude oil, which precipitates due to thermodynamic changes, leading to permeability reduction, alteration of rock wettability, and a decline in production efficiency. In this study, the effect of CO₂ injection on asphaltene precipitation and permeability variations in porous media was modeled using the PC-SAFT equation of state, considering the impact of different clogging models on the results. Initially, the characterization method proposed by Masoudi et al. was improved to provide a more accurate description of the fluid. Then, by reducing the number of required nonlinear equations for simulation, a compositional model was developed, incorporating mass balance equations, the equation of state, deposition models, and clogging models to calculate permeability and porosity changes.
The results indicate that, depending on operational conditions, CO₂ injection can either suppress or intensify asphaltene precipitation. The precipitates primarily form in two key regions: near the production well and at the injection front, significantly affecting permeability and porosity. At the injection front, these changes were minimal, with porosity decreasing from 10% to 9.9%. However, near the production well, a more significant decline was observed, as porosity dropped from 10% to 7.1%, and permeability, depending on the clogging model used, decreased from an initial value of 100 millidarcies to a range of 28–48 millidarcies.
