Experimental and theoretical study of asphaltene deposition and permeability impairment in low-permeability carbonate cores

ABSTRACT

Asphaltene deposition is one of the problems that oil industries face during oil production, processing, transport, and refining. Deposition of asphaltene flocculation on reservoir rock can plug pore spaces and cause permeability impairment. Carbonate rock, which has low permeability, tend to adsorb asphaltene causing more loss of permeability. In this study, three miscible CO₂ injection core tests were conducted at reservoir conditions and the effects of asphaltene content on the amount of formation damage in carbonate cores with low permeability were investigated. High asphaltene content oil has been used in the experiments. Results show that permeability reduction was more than porosity losses. An empirical model for permeability impairment was derived based on experimental data by considering the activation of the two mechanisms simultaneously. The results may be useful for understanding permeability impairment mechanisms during gas injection in low-permeability carbonate cores.

KEYWORDS:

• Asphaltene deposition
• carbonate core
• CO₂
• gas injection
• permeability impairment

Acknowledgments

The authors would like to acknowledge the Petroleum Research Center of PUT (Tehran, Iran) and their staff and researchers.