Prediction of miscible flood performance; The effect of dispersion on composition paths in ternary systems

Abstract

The interaction of phase behavior with dispersive mixing is examined for one-dimensional flow of ternary, two-phase mixtures. For multicontact miscible systems, the quantitative impact of a given level of dispersion (numerical or physical) on displacement composition path is shown to depend on the size and shape of the two-phase region on a ternary diagram. Displacements for systems in which the bubblepoint and dewpoint portions of the binodal curve are nearly parallel are much more sensitive to the effects of dispersion than are systems in which the bubblepoint and dewpoint loci converge toward the plait point. Comparison of solutions obtained by finite differences and by the method of characteristics indicates that a competition between dispersion and sharpening behavior of the leading shock establishes a composition in the two-phase region. Once that composition is established, the subsequent composition path follows that calculated by the method of characteristics.