Study on the Diffusion Behavors of Carbon Dioxide in Reseroir Fluid

• 1、Provincial Hunan Key Laboratory for Cost-effective Utilization of Fossil Fuel Aimed at Reducing Carbon-dioxide Emissions, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082

Abstract：In this paper，the improved gas-liquid diffusion model combined with pressure decay method is proposed for the measurement of effective diffusion coefficients of carbon dioxide in oil-saturated porous at different experimental conditions. The results of the coefficient measurements show that the physical parameters of porous media has a significant influence on the diffusivity of carbon dioxide inside the pores. The comparison of the diffusivities in porous media with and without considering the effect of tortuous path demonstrates great discrepancy, which can lead to a significant deviation in the calculated diffusivities, giving results that are as much as 50 times different than the actual values. The effects of temperature and initial pressure on the diffusion coefficient of carbon dioxide in the oil are also discussed. The results indicate that the diffusivity increases with the increasing of temperature and the increment is increasing; the diffusivity increases steadily with increasing of initial pressure, but the increment is diminishing. For the high pressure conditions, the gas diffusivity in oil-saturated porous had less affected by the pressure, but with the properties of the gas-liquid itself.

Keywords： Chemical engieering diffusion coefficient porous media tortuosity porosity