OPM - Reference Documentation for ewoms

Partially Miscible Three-Phase Model Based on the Black Oil Assumptions. More...

Collaboration diagram for Black Oil:

Files
file	blackoilproperties.hh
	Declares the properties required by the black oil model.

Classes
class	Ewoms::BlackOilBoundaryRateVector< TypeTag >
	Implements a boundary vector for the fully implicit black-oil model. More...

class	Ewoms::BlackOilExtensiveQuantities< TypeTag >
	This template class contains the data which is required to calculate the fluxes of the fluid phases over a face of a finite volume for the black-oil model. More...

struct	Ewoms::BlackOilIndices< PVOffset >
	The primary variable and equation indices for the black-oil model. More...

class	Ewoms::BlackOilIntensiveQuantities< TypeTag >
	Contains the quantities which are are constant within a finite volume in the black-oil model. More...

class	Ewoms::BlackOilLocalResidual< TypeTag >
	Calculates the local residual of the black oil model. More...

class	Ewoms::BlackOilModel< TypeTag >
	A fully-implicit black-oil flow model. More...

class	Ewoms::BlackOilNewtonMethod< TypeTag >
	A newton solver which is specific to the black oil model. More...

class	Ewoms::BlackOilPrimaryVariables< TypeTag >
	Represents the primary variables used by the black-oil model. More...

class	Ewoms::BlackOilProblem< TypeTag >
	Base class for all problems which use the black-oil model. More...

class	Ewoms::BlackOilRateVector< TypeTag >
	Implements a vector representing mass, molar or volumetric rates for the black oil model. More...

Detailed Description

Partially Miscible Three-Phase Model Based on the Black Oil Assumptions.

The black-oil model is a three-phase, three-component model widely used for oil reservoir simulation. The phases are denoted by lower index $\alpha \in \{ w, g, o \}$ ("water", "gas" and "oil") and the components by upper index $\kappa \in \{ W, G, O \}$ ("Water", "Gas" and "Oil"). The model assumes partial miscibility:

Water and the gas phases are immisicible and are assumed to be only composed of the water and gas components respectively-
The oil phase is assumed to be a mixture of the gas and the oil components.

The densities of the phases are determined by so-called formation volume factors:

$B_\alpha := \frac{\varrho_\alpha(1\,\text{bar})}{\varrho_\alpha(p_\alpha)}$

Since the gas and water phases are assumed to be immiscible, this is sufficint to calculate their density. For the formation volume factor of the the oil phase $B_o$ determines the density of saturated oil, i.e. the density of the oil phase if some gas phase is present.

The composition of the oil phase is given by the gas dissolution factor $R_s$ , which defined as the volume of gas at atmospheric pressure that is dissolved in a given amount of oil at reservoir pressure:

$R_s := \frac{\varrho_{o}^G}{\varrho_o^O}\;.$

This allows to calculate all quantities required for the mass-conservation equations for each component, i.e.

$\sum_\alpha \frac{\partial\;\phi c_\alpha^\kappa S_\alpha }{\partial t} - \sum_\alpha \mathrm{div} \left\{ c_\alpha^\kappa \mathbf{v}_\alpha \right\} - q^\kappa = 0 \;,$

where $\mathrm{v}_\alpha$ is the filter velocity of the phase $\alpha$ .

By default $\mathrm{v}_\alpha$ is determined by using the standard multi-phase Darcy approach, i.e.

$\mathbf{v}_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} *\left(\mathbf{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right) \;,$

although the actual approach which is used can be specified via the FluxModule property. For example, the velocity model can by changed to the Forchheimer approach by

SET_TYPE_PROP(MyProblemTypeTag, FluxModule, Ewoms::ForchheimerFluxModule<TypeTag>);

The primary variables used by this model are:

The pressure of the phase with the lowest index
The two saturations of the phases with the lowest indices

Files

Classes

Detailed Description