Asphaltene Deposition during CO2 Flooding in Ultralow Permeability Reservoirs: A Case Study from Changqing Oil Field

Asphaltene deposition is a common phenomenon during CO2 flooding in ultralow permeability reservoirs. The deposited asphaltene occupies the pore volume and decreases permeability, resulting serious formation damage well productivity. It urgent to investigate mechanisms, adverse effects, preventive measures. However, few investigations have been systematically conducted by now. In this research, precipitation mechanisms effects were comprehensively investigated using experimental numerical methods. To study of pressure, content, temperature on qualitatively quantitatively, microscope visible detection experiment PVT cell static firstly conducted. porosity resulted from also studied core experiment. Secondly, simulation models developed validated data. Finally, case Changqing oil field was presented analyze characteristic results showed that increases with increased pressure before reaching minimum miscible (MMP) gets peak value around MMP, while slowly. content. variation trend similar under influence temperature. shows water-altering-gas (WAG) high injection rate suffers more compared WAG low rate, for as MMP. continuous worst choice, sweep efficiency most severe damage. Thus, optimal proposed maintain productivity reduce developing