MRI velocity measurements of water flow in porous media containing a stagnant immiscible liquid

To investigate the flow characteristics of water in a porous medium with a second, stagnant, immiscible liquid phase, we experimentally studied flow of water through a bed of glass beads containing stagnant silicone oil. For imaging, two magnetic resonance imaging (MRI) techniques were used: the chemical shift imaging method and the phase-encoding method. Two-dimensional images both with and without the silicone oil showed that the water velocity profiles drastically changed because the stagnant silicone oil changed the pore structure. Significant changes in flow were also confirmed by composing eleven two-dimensional images of velocity profiles to visualize the three-dimensional flow path and the stagnant silicone oil distribution in the porous media. A statistical method was developed to clarify the relation between pore structure and fluid flow. This method showed that, when stagnant silicone oil is present, but with the same net flow of water, the reduction in rate of flow from large, oil-blocked pores is compensated by an increase in rate of flow from the larger number of small pores.