A method is disclosed for calculating the porosity and permeability of materials using compositional and textural parameters. The step of determining the compositional parameters include identifying the constituent components comprising the sample. From the composition, and with knowledge of the sample area, one can readily identify foreign materials which may affect the porosity and permeability. Furthermore from the composition, the samples may be readily grouped or classified with samples having similar composition. The method provides one manner of discriminating between such samples. Following composition, the sample is disaggregated and the grain size distribution is determined. From the grain size, and following a correction/adjustment to the distribution, an optimum grain index is calculated. The optimum grain index is then correlated to a porosity coefficient which is then used to calculate the porosity. From the porosity, permeability is readily calculated based upon recognized relationships. The results of the method produce an output correlating the porosity to permeability as a function of sample location. <IMAGE>
