MULTISCALE GEOMETRICAL RECONSTRUCTION OF POROUS STRUCTURES

Multiscale percolation systems (MPSs) were proposed to study invasion processes in porous media with a large pore size distribution, conside ring the porous section as a polydisperse structure that modifies its geometrical structure when the scale of observation is changed. Multis cale models are nonregular percolation systems and do not have the fol lowing limitations common to classical percolation systems: (i) It it not necessary to choose a particular value for the coordination number Z nor to establish a particular distribution law for it and (ii) cons trictions appears naturally as pores of smaller diameters connecting p ores of gr-ater diameters, as the result of superposing different scal es. A fundamental question that arises in this method is related to th e conservation of the spatial connectivity between the pores, which is very important if MPS models are to be used for simulating fluid rete ntion and transfer. The present work is focused on this problem. It is shown that, although conserving the classical correlation function at the object level, i.e., pores, the use of a MPS as a representation o f a porous medium does not allow for the conservation of the geometric al structure of clusters of connected pores. An improved MPS model is discussed.