TITLE:
Effect of Heterogeneity of Porous Media on Gas Permeation and Entrapment
AUTHORS:
Yohei Mikami, Yoshihiro Deguchi, Tetsuya Suekane
KEYWORDS:
Carbon Dioxide Capture and Storage (CCS), Residual Gas Trapping, X-Ray CT, Capillarity
JOURNAL NAME:
Journal of Flow Control, Measurement & Visualization,
Vol.2 No.3,
July
24,
2014
ABSTRACT: Capillary trapping prevents the migration of CO2 in reservoirs due to buoyancy. The residual gas saturation is strongly influenced by the gas saturation after gas injection. In this study, we have investigated the effect of stratified structure of heterogeneous porous media on gas permeation and entrapment. Experiments were carried out at a laboratory condition for a nitrogen-water system with the packed beds of glass beads with various diameters which modeled stratified porous media. In the case of parallel structure, the injected gas selectively percolated into permeable layers. The gas permeation can hardly occur for the less permeable layers because of the capillary entrance pressure. In the case of serial structure, the interface of porous structure hindered the migration of gas across it, because of the capillary entrance pressure. When the gas percolated in the permeable layers, capillary fingering was developed in the layers. However, when the tip of finger reached the interface, fingers grew in tangential directions until the pressure built up to overcome the capillary entrance pressure. As a result, high gas saturation was achieved in the permeable layers of both upward and downward gas injections.