One- and Two-Phase Permeabilities of Vugular Porous Media

The single and double phase macroscopic permeabilities of bimodal reconstructed porous media have been studied. The structure of these bimodal media is characterized by the micro and macroporosities (vug system) and by the micro and macrocorrelation lengths l _p and l _v. For a single phase, if the vugular system does not percolate, it is shown that the absolute permeability K mainly depends on l _p and very little on the other parameters. However, when the vugs percolate, K is also influenced by the density of vugs. For double phase calculations (in strong wettability conditions), it is shown that a vuggy percolating system affects mainly the nonwetting phase permeability. Moreover, the relative permeabilities for a nonpercolating vuggy system are only slightly influenced by the porosity distribution. These predictions are in good agreement with some experimental data obtained with limestones.     

Macroscopic Conductivity of Vugular Porous Media

A systematic numerical study of the macroscopic electrical conductivity of vugular porous media has been conducted by solving the Laplace equation. The structure of these bimodal media is characterized by the micro and macroporosities and by the micro and macro correlation lengths. The overall correlation function is analyzed. It is shown that mainly depends on the total porosity, and very little on the other parameters. Moreover, similar results are obtained when the microporous medium is considered as a continuum. Finally, these predictions are compared to experimental data for the formation factor and the thermal conductivity of limestones; the agreement is good in the first case, and excellent in the second.