Analysis of a compositional model for fluid flow in porous media

In this paper we consider a compositional model for three-phase multicompon ent fluid flow in porous media. This model consists of Darcy's law for volu metric flow velocities, mass conservation for hydrocarbon components, therm odynamic equilibrium for mass interchange between phases, and an equation o f state for saturations. These differential equations and algebraic constra ints are rewritten in terms of various formulations of the pressure and com ponent-conservation equations. Phase, weighted fluid, global, and pseudoglo bal pressure and component-conservation formulations are analyzed. A numeri cal scheme based on the mixed finite element method for the pressure equati on and the Eulerian-Lagrangian localized adjoint method for the component-c onservation equations is developed. Numerical results are reported to show the behavior of the solution to the compositional model and to investigate the performance of the proposed numerical scheme.