EXODUS v9.00

EXODUS is a general purpose K-value compositional model for simulating black oil, gas or gas condensate, coal bed methane, volatile oil reservoirs. The compositional formulation of the model accurately represents phase behaviour for treatment of variable bubble points, mixing of different PVT regions, tracer tracking and differentiation of injected and in-place fluids. The transfer of any component between the oil, gas and water phases is calculated using equilibrium ratios. Black oil data are internally converted to compositional equivalents. The model may also be used for polymer, alkaline-surfactant-polymer simulation.

The program can simulate problems in one, two or three dimensions using either rectangular cartesian (x y z) or cylindrical (r θ z) coordinates, with any combination of oil, gas or water phases, and characterizing the reservoir fluid into one or more components. Interblock mass transfer is represented by Darcy’s law with relative permeability, capillary pressure and gravity effects. The reservoir description capability includes naturally fractured reservoirs, and communicating faulted reservoirs. Dual porosity/dual permeability reservoirs may be simulated. The model also allows special connection of non-neighbouring grid cells for unconventional problems. Wells can be deviated or horizontal. Multiphase correlations are fully coupled to provide pressure losses in the vertical tubing. The model will also calculate multiphase pressure losses in long horizontal producers.

The reservoir model can also be coupled to a surface gas gathering network fully implicitly. The surface network description includes parallel, looped lines, field compressors. Multiple offtake points with gas contracts may be specified.
EXODUS has non-linear regression capability built into it whereby the program user may find the best values of porosity, permeability, relative permeability that will match observed field history. This is commonly known as automatic history matching. This feature is of great value in reducing the time required to obtain a history match.