Well-logging techniques provide continuous profiles of various in situ physical properties like the bulk density, the photoelectric effect, and the natural gamma radioactivity of geological formations. Our purpose is to use this information to determine a continuous profile of the mineralogy with depth. The well-log derived mineralogy is then combined with a petrophysical model to infer continuous permeability and saturation profiles in chlorite-bearing sandstone formations. Our mineralogical inversion algorithm combines a cluster analysis of the raw data and their inversion using the generalized nonlinear inverse method developed by Tarantola and Valette <1982>. A field case is treated concerning a borehole intersecting an alternation of sandstones and shales. The mineralogical logs we obtained are in very good agreement with the mineral proportions measured independently on core samples. Mineralogical profiles are combined with a specific textural model to derive a continuous profile of permeability. We found a very good agreement between this computed permeability log and independent core permeability measurements over 3 orders of magnitude.