This study presents an investigation of the flow mechanism of carbon dioxide (CO2) through nano and micro pores and the impact of this flow on oil mobilization and asphaltene instability in the crude oil. The flow mechanism of CO2 is determined using numerical modeling through the Knudsen number to determine the flow regimes under different thermodynamic conditions. Following this, the oil production and asphaltene stability are studied using a filtration vessel supplemented with nano and micron sized filter membranes. The effect of varying CO2 injection pressure, oil viscosity, porous media pore size, and porous media thickness on oil mobilization and asphaltene stability are studied. Regarding the flow regimes, it is found that four distinct flows are observed during CO2 injection in the nano and micro pores. These flow regimes included diffusion, transition, slippage, and viscous flow. As the pore size increases, the flow becomes viscous dominated. Crude oil flow through the nano pores required higher pressure and also resulted in more severe asphaltene damage and plugging compared to the micro pores. Increasing the CO2 injection pressure increased oil production and decreased the asphaltene concentration in the bypassed crude oil, which is the oil remaining in the filtration vessel and could not be produced. The lower oil viscosity is associated with a lower asphaltene concentration and thus yields an overall higher oil viscosity as well. By undergoing this research, a better understanding of how the CO2 flows through nano and micro pores can be achieved, and oil mobilization and asphaltene instability with time can also be understood.


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Asphaltene instability; Carbon dioxide flow; Micro and nano pores

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Document Type

Article - Journal

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Final Version

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Publication Date

01 Jun 2020