Experimental Investigation and Modeling of Permeability Impairment Mechanisms Due to Asphaltene Precipitation Under CO_2 Injection Conditions

摘要

The injection of hydrocarbon gases/CO_2 for enhanced oil recovery can promote asphaltene precipitation and consequently reservoir impairment, of which its impact is tremendous. In this work, the results of flow dynamic tests performed on sandstone as well as carbonate rocks were presented. The permeability reduction mechanisms were investigated during simultaneously injection of CO_2 and recombined oil into core samples through a static mixer at reservoir conditions. The permeability impairment data was monitored from analysis of recorded pressure and online viscosity measurements during the experiments. Analysis of obtained results revealed that for both sandstone and carbonate rocks, surface deposition and pore plugging mechanisms participate simultaneously in reduction of permeability in primary injected pore volumes. Therefore, a new permeability reduction model is proposed that considers a combination of surface deposition and pore plugging mechanisms. The results of the new model are in good agreement with the obtained experimental data. The results of this work can be helpful for modeling of asphaltene deposition due to CO_2 injection in petroleum reservoirs.