f Transport properties of rocks: results and models

Transport properties of rocks (i e. permeability and electrical conductivity) have been for a long time investigated using empirical models. This situation is of course the result of the complexity of rocks, which are both porous and heterogeneous. The recent development of new theoretical and microstructural quantitative tools has however modified this. Methods derived from statistical physics, well suited to heterogeneous media, have been applied to rocks. Percolation theory has proven to be a fruitful framework when applied to permeability and conductivity. Image analysis and mercury porosimetry have been used as input data to quantitatively predict permeability, conductivity and even their pressure dependence . These recent advances are briefly presented in two close but distinct ways: first statistical and percolation models allow to calculate permeability and conductivity; second the Huid paths can be analysed and described by these models. Both points are crucial since they concern the two following questions: what is the Huid flux through the rock (permeability) ? and where does the Huid flow (fluid path) ?