Investigation of gas injection flooding performance as enhanced oil recovery method

• Effects of supercritical CO2 and N2 injection on live oil recovery were investigated.
• Precipitation of asphaltene was also examined.
• Depositions of asphaltene were not observed during SC-CO2 injection.
• MCM and FCM of live crude oil/N2 are considerably higher than live crude oil/CO2.

Asphaltene precipitation and deposition within the reservoir formation is one of the main concerns during enhanced oil recovery (EOR) processes especially during the gas injection. In the current study, different aspects of carbon dioxide (CO2) and nitrogen (N2) injection in the reservoir, was thoroughly examined. The feasibility of using these gases as the injection gas was explored using Bayesian network-based screening method. After recombination and preparation of the live crude oil, precipitation of asphaltene using vanishing interfacial tension (VIT) method and core flooding experimentation was examined. Besides, swelling test was utilized to investigate the effect of CO2 and N2 injection on the expansion of live crude oil. The obtained results showed that recovery factor (RF) of CO2 injected method in core flood test is higher than N2 injection due to higher swelling and better miscibility conditions. Although, VIT measurements showed asphaltene precipitation during CO2 injection, no sign of asphaltene deposition during core flood test at near bubble point pressure was observed.

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