ABSTRACT
This chapter proposes a methodology for the incorporation of soft geological information in addition to the available hard data in order to characterize geological heterogeneity under two scales of variability. The approach is referred to as the hybrid stochastic approach. A mixture-of-populations model is used as a tool to mathematically describe this type of heterogeneity. The core of the model is the analysis of field samples from different populations. Each population is characterized by its own statistical distribution and parameters. The purpose of geometrical modelling of large scale variabilty is to identify geological zonation which describe features with discrete nature. The coupled Markov model is used to characterize this scale of variability using soft information. Large scale field studies on spatial variability would be a proper test to evaluate and validate the proposed hybrid model.
