Contact Characteristics and Characterization Methods of CO2 and Crude Oil in Visual Porous Medium

Abstract

In this article, the vertical static variation characteristics of CO2 and crude oil in porous medium under different experimental pressures are studied by using the CO2 miscible visual displacement device jointly developed. The process of change at the CO2 and crude oil interface is characterized by relative height and dissolution expansion rate. Experimental results demonstrate that with the increase of pressure, CO2 gradually reaches a supercritical state with strong extraction and mass transfer capacity, and CO2‐crude oil exhibits different contact forms under different pressures. Under the same pressure, there are also significant differences in contact forms between visual tube and porous medium. The existence of porous medium weakens the mass transfer and diffusion abilities between CO2 and crude oil and reduces the extraction of light components by CO2. In porous medium, the relative height of crude oil is a power function of time, which is 1/5 ≈ 3/10 of that in visual tube. And the dissolution expansion rate of CO2 and crude oil exhibits a negative logarithmic correlation with time, which is 1/4 ≈ 2/5 of that in visual tube. The impact of porous media on relative height and dissolution expansion rate of crude oil becomes more pronounced as the pressure decreases.