Computer Simulation of Compositional Flow Using Unstructured Control Volume Finite Element Methods

Abstract

In this paper, we study the computer simulation of gas cycling in a rich retrograde condensate reservoir. Two prediction cases are studied. The first case is gas cycling with constant sales gas removal, and the second case is cycling with some gas sales deferral to enhance pressure maintenance in the early life of this reservoir. In this problem the great majority of cycling takes place at pressure below the dew point pressure, indicating the need for modeling the compositional three-phase, multicomponent flow in the reservoir. This compositional model consists of Darcy's law for volumetric flow velocities, mass conservation for hydrocarbon components, thermodynamic equilibrium for mass interchange between phases, and an equation of state for saturations. The control volume finite element (CVFE) method on unstructured grids is used to discretize the model governing equations for the first time. Numerical experiments are reported for the benchmark problem of the third comparative solution project (CSP) organized by the society of petroleum engineers (SPE). The PVT (pressure-volume-temperature) data are based on a real fluid analysis.