Experimental study of the supercritical CO ₂ diffusion coefficient in porous media under reservoir conditions

Abstract

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

Edible oils as a co-extractant for the supercritical carbon dioxide extraction of flavonoids from propolis

“…Among the oils used, the diffusivity was the highest in scCO 2 -VCO which relate to viscosity of oil used in the study. As reported by [ 47 ], the diffusivity is inverse proportional to viscosity and as discussed earlier that VCO had the lowest viscosity as compared with CO and G. In particular, the use of scCO 2 –VCO at 150 bar to 250 bar at 50°C the diffusivity was increased and high yield was obtained because the matrix diffusivity was directly correlated to the mass transfer process [ 46 ]. Pressure has also found to be direct proportion to diffusivity by Lv et al .…”

Mechanisms of tripartite permeability evolution for supercritical CO2 in propped shale fractures

“…Besides, the increasing density of supercritical CO2 generates more molecular layers attaching to the surface, thus enhancing the total absorbed mass (Klewiah et al, 2020;Rother et al, 2013). The higher diffusibility of supercritical CO2 also increases the interaction surfaces by diffusing into more pores and deeper into the matrix (S. Li, Li, & Dong, 2016;Lv, Chi, Zhao, Zhang, & Mu, 2019). Therefore, increasing sorption sites, enabling sorption of multilayered molecules and increased diffusion rate of supercritical CO2 may all contribute to secondaryadsorption (Fig.…”

Experimental Determination of CO2 Diffusion Coefficient in a Brine-Saturated Core Simulating Reservoir Condition

“…where C is the concentration of CO 2 in the core, mol/m 3 ; r is the radius of CO 2 diffusion; 0 < r < r 0 , m; r 0 is the core radius, m; t is the diffusion time, t ≥ 0, s; D eff is the CO 2 effective diffusion coefficient, m 2 /s. After conversion and simplification, the formulas for calculating the CO 2 diffusion coefficient are as follows [8,44].…”