Several
investigators have recognized that an accurate description of multiphase flow in a porous medium must account for the thermodynamics and the geometry of the interfaces between the fluids. Muccino et al. (1998) for instance hypothesized that the capillary pressure - saturation relationship is a two-dimensional projection of a more extensive functional dependence, i.e., a third variable is needed to explicitly define the state of the system. They propose
that the third variable is interfacial area per volume (IAV).
This work is motivated by the desire to measure IAV directly, and for a fully three-dimensional system. We use synchrotron based x-ray microtomography to measure IAV in packed glass bead columns or for more natural systems) sands, crushed volcanic tuff). Fully three dimensional images are collected at points on the drainage and imbibition curves. Analysis of the high-resolution images (genrally 5-15 micron voxels) allows for computation of interfacial areas, saturation, and curvature. Corresponding pressure measurements are made during the course of the experiments.
We currently have CMT data for a number of different porous systems, fluids, wettability, and image resolution, - more information can be found on our data information page.
Currently, data for an air-water-glass bead system and an oil-water-glass bead system have been published, as well as comparison to lattice-Boltzmann simulations (link to come).
|
