Visualization of 2D diffusion phenomena in rock by means of X-ray CT

X線CTによる岩石中の2次元拡散現象の可視化について

佐藤 晃*; 深堀 大介*; 菅原 勝彦*; 澤田 淳 ; 武部 篤治*

Sato, Akira*; Fukahori, Daisuke*; Sugawara, Katsuhiko*; Sawada, Atsushi; Takebe, Atsuji*

単一の平行平板亀裂を含む岩石試料を対象とした二次元拡散実験を実施し、非収着性トレーサーが亀裂から岩石マトリクスへ拡散する様子についてX線CTを用いた可視化を行った。密度の高いトレーサーが亀裂から岩石マトリクスへ二次元的に拡散することによるCT値の増加を観察することができ、これに画像処理技術を適用することでより鮮明な画像を得るとともに、拡散現象の解析に有用なデータを得ることができた。二次元拡散試験の結果は数値解析結果とも比較可能で、適切な画像処理技術を用いることでX線CTを用いた岩石中の拡散現象の可視化手法の適用性を明示できた。

The two dimensional (2D) diffusion tests with the rock sample which has single plane crack were conducted, and the diffusion of non-sorbing tracer from the crack to rock matrix is visualized by X-ray CT in this study. It was found that the increment of CT value due to the 2D diffusion of the dense tracer from crack surface to the matrix of rock sample was observed. It was also found that the application of image processing techniques makes it possible to obtain the clear image data and that the precious analysis of diffusion phenomena becomes possible. The numerical simulation was also conducted in order to verify the experimental results. The results of 2D diffusion tests show good agreement with the numerical results, and the applicability of X-ray CT to the analysis of diffusion phenomena in a rock sample was verified together with the necessary image processing techniques.