Migration of carbon dioxide in sandstone under various pressure/temperature conditions: From experiment to simulation

Abstract

The pressure and temperature of a target CO 2 storage reservoir can significantly affect the migration and relative permeability characteristics which can ultimately determine the carbon storage capacity and storage integrity of target formations. To understand these impacts, a CO 2 core-flooding experiment was conducted on a brine-saturated sandstone containing a single clay interlayer perpendicular to the flow direction at a temperature of 313 K and a pressure of 8 MPa and the fluid distribution was monitored by a high-resolution X-ray computed tomography (X-CT) scanner. Further, a one-dimensional model was established to reproduce the CO 2 flow behavior inside the sample under the same experimental condition and then the model was extended to different temperatures (313 and 350 K) and pressures (6,8,12, and 17.4 MPa). The experimental results show that the CO 2 preferentially created high-CO 2 -saturation flow pathways which then expanded until they were large enough to transport the CO 2 at the prescribed flow rate. The sub-core scale heterogeneity also had significant effects on the CO 2 migration, forming a barrier to downstream flow. The simulation results show that at a given temperature, the CO 2 front migration velocity decreased with increasing reservoir pressure while the CO 2 saturation along the pathways increased. Comparing simulations when the reservoir pressure was the same, the front-migration velocity increased with increasing temperature, and the CO 2 saturation along the pathways decreased. Meanwhile, the influence of temperature and pressure on CO 2 saturation distribution was more evident in the parts of the core with high residual brine saturation.

Long‐term CO2 sequestration mechanisms and influence of injection mode in Zhujiang Formation of Pearl River Mouth Basin

“…2b, which is smoothed experimental data measured under reservoir conditions. Based on the large porosity and permeability of the reservoir model, the calculated capillary entry pressure was particularly small 45 . Thus, the capillary pressure curve was not considered in this study.…”

“…Based on the large porosity and permeability of the reservoir model, the calculated capillary entry pressure was particularly small. 45 Thus, the capillary pressure curve was not considered in this study. To simulate the CO 2 mineral trapping process, the primary mineral compositions of Zhujiang Formation and possible secondary mineral phases are listed in the Table 1.…”

Reciprocal cross‐correlation analysis of two‐phase seepage processes and reservoir heterogeneities in CO2 saline aquifer sequestration

“…In this study, COMSOL finite element numerical simulation software was used to simulate the two-phase seepage process of CO 2 saline aquifer sequestration, and the two physical fields of Darcy's law for porous media and phase transport were called in the software to simulate the two-phase seepage equations 34 as follows:…”

“…where ϕ is the porosity (%), S α is the saturation of the α phase, ρ is the density (kg/m 3 ), t is the time (s), k rα is the relative permeability of the α phase, μ is the dynamic viscosity (m 2 ) and p α is the pressure of the α phase, Q α is the source/sink of α phase. The values of the capillary entry pressure and its components are obtained from Xu et al 34 :…”

“…Based on a study by Xu et al, 34 numerical values were obtained for capillary entry pressure, capillary function, and its components.…”