Abstract
Combined ultrasonic and X-ray microtomography measurements in situ at high pressure, in conjunction with lattice-Boltzmann simulations, enabled simultaneous investigation several physical parameters including: elastic wave velocities (v(p) and v(s)); apparent Poisson's ratio; pore structure; porosity; and permeability. Experiments were conducted on a simple analog material, porous mold-quality aluminum, in a Paris-Edinburgh cell from 0.14 to 1.36 GPa. Porosity was observed to have a strong inverse dependence on pressure up to similar to 0.9 GPa, while permeability has an anisotropic dependence on pressure. Elastic wave velocity (v(p), v(s)) and apparent Poisson's ratio all increase with pressure, with v(p) agreeing well with the Hashin-Shtrikman upper bound at lower pressures and higher porosities. These results demonstrate a new methodology combining experimental and analytical methods to provide cross-property links between microscopic structure and macroscopic elastic properties. Future investigations on more complex Earth materials may have important implications for our understanding of the composition of the deep Earth.