Effects of asphaltene deposition-derived formation damage on three-phase hysteretic models for prediction of coupled CO2 enhanced oil recovery and storage performance

Abstract

Asphaltenes, precipitated from oil due to pressure, temperature, or oil compositional changes, can affect not only the performance of CO2 enhanced oil recovery (EOR), but also carbon capture and storage (CCS) by reducing porosity and permeability and altering wettability. A comprehensive solid deposition model, which includes adsorption, pore throat plugging, and re-entrainment, was developed to predict the amount of precipitated asphaltene under dynamic conditions. In this study, a hysteretic three-phase fluid flow model was used to simulate residual and solubility trapping during the water alternating gas (WAG) process. Alteration of rock wettability during asphaltene deposition led to a decrease in oil and gas mobility and an increase in water mobility, increasing the amount of CO2 residual trapping to 39%, via a hysteresis effect. Residual trapped CO2 replaced liquids in the pore space; more water was substituted when asphaltene deposition was considered than that without it because of greater water mobility. Consequentially solubility and residual trapping were overestimated by 20% and underestimated by 39% when asphaltene deposition was not considered. Formation damage by asphaltene deposition increased water production by 14% and decreased oil recovery by 9% compared to a model without asphaltene deposition. These results indicate that asphaltene deposition affects CO2 trapping mechanisms and EOR performance during coupled CO2 EOR and storage processes.