Contaminant Transfer Simulation of Unsaturated and Multiphase Flows in Porous Media

The ability to numerically simulate single phase and multiphase ow of uids in porous media is extremely important in developing an understanding of the complex phenomena governing the ow. The ow is complicated by the presence of heterogeneities in the reservoir and by phenomena such as diiusion, dispersion, and viscous ngering. These eeects must be mod-eled by terms in coupled systems of nonlinear partial diierential equations which form the basis of the simulator. The simulator must be able to handle both single and multiphase ows and the transition regimes between the two in unsaturated ow applications. A discussion of some of the aspects of modeling unsaturated and multiphase ows in the presence of heterogeneities and viscous ngering is presented along with directions for future work. Simulators are severely hampered by the lack of knowledge of reservoir properties, hetero-geneities, and relevant length scales and important mechanisms like diiusion, dispersion, and viscous instabilities. Recent developments have been made in homogenization, scaled averaging , and the use of the simulator as an experimental tool to develop methods to model the interrelations between localized and larger scale media eeects.