Compositional grading with a depth in gas-oil reservoirs

This work deals with some problems of the compositional grading with a depth (CG) connecting to the construction of PVT fluid models for the gas-oil reservoirs simulation. There are given the problem formulation and algorithms for the CG including searching for the gas-oil contact (saturated and undersaturated) in isothermal approach. Some examples of the numerical calculations are presented. Some weaknesses of component grouping operation are demonstrated as well as the reasonability of component — fraction splitting to subfractions is shown for CG problem.