Simulation of multiphase and compositional flow in porous media

Ground contaminations by non-aqueous phase liquids have become in recent years a problem of increasing concern. To get a better understanding of the processes and to develop in-situ remediation techniques numerical simulations of such multiphase and compositional flow problems are necessary. We will show a family of multiphase-multicomponent simulators which are based on a new consistent finite volume (box) scheme formulation with an efficient multigrid algorithm. The concept of global mass fractions is incorporated into the system of equations. For the simulation of multiphase flow there are several options for the choice of primary. variables. This is because a Newton-Raphson iterative scheme is used to solve the system of equations which is combined with a numerical differentiation of the partial derivatives with respect to the primary variables. Several two- and three-dimensional example problems are investigated. First, to show the physical processes which take place and, second, to demonstrate the performance of the different simulators. In one example the validity of the passive air phase assumption in the case of a LNAPL infiltration is investigated.