NEW LABORATORY DATA BASED MODELING OF MISCIBLE DISPLACEMENT IN COMPOSITIONAL SIMULATION

摘要

This paper discusses a new approach that relates primarily to the laboratory and modeling studies that precede the Equation of State(EOS) based compositional simulation of miscible displacement. Multi-phase flow through porous media is governed by the interaction between capillary, viscous and gravitational forces.The flow regime can be characterized by the capillary number,Nc and the Bond number,Nb,which are defined as dimensionless measures for the ratio of - viscous and capillary - and - gravitational and capillary - forces at the pore scale. The importance of these factors in designing an accurate EOS characterization and phase behavior of the reservoir fluids coupled with the flow through porous media considerations to obtain an accurate description of PVT and reservoir rock data for use in compositional simulation will be reviewed. The determination of miscibility conditions by advanced reservoir fluid studies is discussed along with a special core flood experiment design for measuring the interfacial tension dependent relative permeabilities. In the commercial EOS based compositional simulation software packages,the conventional belief is that using an ideal relative permeability curve to correspond to total miscibility and scaling these curves for given conditions is satisfactory.Also assumed is that the impact of the errors introduced on recoveries is minimal.These assumptions might hold true for homogeneous media and ideal miscibility conditions only. For a dynamic description of flow regions during miscible displacement process,a new laboratory data based model of interfacial tension dependent of relative permeability and capillary pressure data is presented.Also presented are the advantages of incorporation of this model in the commercial EOS based compositional simulation software packages.