Simulation of Compositional Flooding Using Third-Order Difference Techniques

Abstract

ABSTRACT Conventional compositional simulators based on low order discretization techniques introduce unacceptably high levels of numerical dispersion and anisotropies (grid orientation sensitivity) when applied to miscible or multicontact miscible displacement processes. A simple, uniformly third order finite-difference scheme is developed which successfully overcomes these problems. A novel modification to the leading truncation term allows solutions to be obtained which are insensitive to grid orientation without reducing the order of accuracy of the solution. The high order schemes developed are applied to one-dimensional multicontact miscible displacements where they are shown to predict recoveries considerably different to those obtained with low order schemes. In two-dimensional miscible displacements the high order method is used to study the growth of viscous fingers and the effect of gravity segregation in the presence of strong compositional effects. Comparisons with results obtained using low order methods suggest that the high order scheme has the potential to significantly reduce the computational effort involved in compositional simulation.