The simulation of multivariate petrophysical relationships between core and well-log derived parameters on the example of the South Caspian Basin is discussed. For developing the petrophysical relationships, a number of deterministic and stochastic calculating procedures are used by the authors. These relationships are widely used in petroleum geology and reservoir engineering for hydrocarbon reserves estimation, reservoir description and simulation, field development planning, and reservoir production management.Petrophysical relationships or petrophysical models are used to describe actual correlation existing among various core-derived parameters (core-to-core correlation) and to improve reliability and accuracy of wireline log analysis and interpretation on the basis of correlation between log and core petrophysical parameters (log-to-core correlation). Petrophysical relationships are widely used in petroleum geology and reservoir engineering for hydrocarbon reserves estimation, reservoir description and simulation, field development planning, and reservoir production management.Because of the multitude of variables involved in petrophysical relations, the most effective methodology of petrophysical simulation is statistical analysis. Very important is the description of regional distribution of such pertophysical properties as porosity and permeability, and their changes with depth of burial. The standard practice used to study regional distribution of any core-derived parameter is a construction of maps with contour lines or zonal maps, which are defined as two-dimensional images or models of a given reservoir feature. To study the distribution of petrophysical parameters over the entire field, the 3D statistical analysis is implemented.Methodology of computation of relationships among petrophysical and other geological parameters is described in many publications (e.