Abstract

The negative side effect of the flooding with CO₂ is asphaltene deposition; while little work was reported in the literature on asphaltene precipitation due to CO₂ flooding in presence of light components. The main objective in this paper is to address asphaltene precipitation for oil containing methane and propane due to CO₂ flooding at different miscibility conditions. Experimental measured asphaltene deposition due to miscible CO₂ injection is compared with corresponding values estimated by proposed model. It is shown that there is a critical concentration of CO₂, where below it; solubility parameter of the liquid is enhanced, hence preventing asphaltene from depositing. The first objective of the paper is to address an approach which is based on solubility parameters/CO₂ fraction in the liquid to qualitatively assess stability/instability region for the asphaltene. The second objective is to quantitatively compare the predicted and experimental results. It is shown that the higher CO₂ flooding pressure and temperature, the more deposited asphaltene. It was also shown that a higher risk for asphaltene deposition in case of chalk cores than for sandstone cores.

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