No abstract

Geological sequestration of carbon dioxide (CO 2 ) is an effective method to achieve a substantial reduction in CO 2 emissions to the atmosphere at a relatively low cost; however, the migration process of CO 2 in deep saline aquifers has not been clarified. In order to evaluate the storage site and assess the CO 2 leakage risks and storage costs, fundamental visualization and study of immiscible two-phase flow in sandstone are required. This study observed the behavior of liquid CO 2 injected into water-saturated Berea sandstone by using microfocus X-ray computed tomography with high spatial resolution. The three-dimensional CO 2 distribution in the sample was clearly reconstructed. The bedding structure of the rock strongly determined the CO 2 permeation process, and a strong correlation was seen between the local porosity of the sample and the CO 2 saturation. The real time CO 2 permeation process was also observed in the transparent images that showed the CO 2 gradually permeating the rock in the axial direction with increased saturation in the higher porosity beddings. The effects of the sandstone micro-heterogeneity on the behavior of the injected liquid CO 2 are discussed.

Carbon capture and sequestration (CCS) is part of the global challenge to mitigating global warming and climate change. Geological sequestration of carbon dioxide (CO 2 ) is an immediately available and technologically feasible method for achieving a substantial reduction in carbon dioxide emissions into the atmosphere. Because injected CO 2 migrates upward in an aquifer owing to the buoyancy force, a highly impermeable layer is generally employed to prevent CO 2 leakage from the storage reservoirs. For these reasons, assessment of the storage site, leakage risks, and storage costs are one of the main issues in CO 2 geological sequestration. The intent of the present study is to clarify the fundamental mechanism of buoyancy driven CO 2 in a porous media. The behaviour of liquid CO 2 in water-saturated silica packed bed was observed using high spatial resolution X-ray computed tomography. As the result, CO 2 migration in porous media was visualized with 20 µm resolution, and it was found that the CO 2 migration speed was mostly dominated not by the viscous resistance of CO 2 itself but by that of the surrounding water. 緒 言

No abstract

No abstract