A CONSISTENT APPROACH FOR APPLYING NUMERICAL BOUNDARY-CONDITIONS FOR MULTIPHASE SUBSURFACE FLOW

The partial differential equations which model multiphase subsurface f low are, in general, of mixed parabolic-hyperbolic type. A consistent and unified approach for handling a wide variety of boundary condition s under all flow conditions is presented. This method is conceptually simple, and numerically efficient. Test computations are presented whi ch demonstrate this method for saturated-unsaturated models, and well as true three-phase simulations. Among the boundary conditions discuss ed are: seepage face conditions for three-phase problems and multi-nod e constant-rate pumping wells.