低炭素社会構築のためのCCS

[1K0701-09-08] Experimental study on the drainage displacement patterns in three dimensional porous media

○Yingxue Hu¹, Tetsuya Suekane¹ (1. Tokyo Institute of Technology)

Keywords:drainage, displacement patterns, porous media, storage efficiency, X-ray

Characterization of immiscible fluid drainage displacement in porous media is of great importance in carbon capture and storage. The phase diagram of displacement patterns affects the storage efficiency in subsurface processes. This work experimental studied the immiscible displacement in an unconsolidated packed bed at the pore scale with a wide range of capillary number and viscosity ratio using X-ray microtomograpy. Typical displacement morphologies were observed, including viscous fingering, capillary fingering and stable displacement, and a phase diagram for three-dimensional porous media was proposed. The characterization of the displacement patterns (fractal dimension and finger width) was analyzed to reveal the mechanism how the displacement pattern affects the storage efficiency. Additionally, the invasion dynamic of non-wetting phase before and after breakthrough time were compared for typical viscous fingering and capillary fingering. The defending fluid could be trapped by bypass flow in capillary fingering, which decides the storage efficiency in geological carbon sequestration. Our results provide an understanding from pore scale view on how the displacement pattern affects the displacement or storage efficiency in three-dimensional porous media. Furthermore, the phase diagram under various conditions could help to find a suitable reservoir conditions for carbon capture and storage.