岩石内にトラップされる微細気泡の可視化(流体工学,流体機械)

概要

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Entrapment of non-wetting phase in porous media has been observed in variety of fields such as petroleum engineering, geological storage of carbon dioxide, and remediation of ground. We investigated the residual gas trapping from a microscopic point of views. High-resolution, three-dimensional images of pore structure and trapped gas bubbles in Berea, Tako, and Shirahama sandstones were obtained using a micro-focused X-ray CT scanner. The trapped bubbles consist of two-type; one occupies the center of pore with a pore-scale size and the other has a pore-network scale size. Even in the pore with a trapped gas bubble, wetting-phase imbibes into the pore through its corner depending on the structure and surface roughness. The maximum pore diameter and the maximum trapped bubble diameter were estimated from CT images. The maximum trapped bubble diameter is in the range from 10 to several hundreds as large as the median of pore throat diameter. Finally, the specific area ratios of pores and bubbles were estimated.
2008-12-25