Eur. Phys. J. B 50, 631-637 (2006)
https://doi.org/10.1140/epjb/e2006-00168-y

Numerical studies of gravity destabilized percolation in 2D porous media

¹ Key Laboratory of Mineral Resource, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, P.R. China
² Laboratoire de tectonophysique (UMR5568), ISTEEM, CNRS & Université Montpellier II, 34095 Montpellier, France
³ SISYPHE, UMR, Boîte 123, Université Paris 6, 75252 Paris Cedex 05, France

Corresponding author: ^a loggia@univ-montp2.fr

Received: 22 April 2005
Revised: 3 January 2006
Published online: 17 May 2006

Abstract

Two dimensional simulations of percolation are realized on square networks of pore throats with a random capillary pressure distribution. We analyse the influence of a destabilizing gravity field (g) and of the standard deviation of the distribution of the capillary pressure thresholds (W_t). The fragmentation process is not taken into account in this study. For an increase of g or/and when W_t decreases, two transitions are analyzed with three different regimes displacement patterns: Invasion percolation, invasion percolation in a gradient, and invasion in a pure gradient. The transitions are controlled both by the ratio g/W_t and by the sample size (L). A scaling law between the saturation at the percolation threshold and g/W_t allows delineating the three regimes in agreement with theoretical argument of the percolation in a gradient.