# PorousFlowPeacemanBorehole

A PorousFlowPeacemanBorehole is a special case of the general line sink in which a polyline (represented by a sequence of points) acts as a sink or source in the model. Please see sinks for an extended discussion and examples.

## Input Parameters

• characterIf zero then borehole does nothing. If positive the borehole acts as a sink (production well) for porepressure > borehole pressure, and does nothing otherwise. If negative the borehole acts as a source (injection well) for porepressure < borehole pressure, and does nothing otherwise. The flow rate to/from the borehole is multiplied by |character|, so usually character = +/- 1, but you can specify other quantities to provide an overall scaling to the flow if you like.

C++ Type:FunctionName

Options:

Description:If zero then borehole does nothing. If positive the borehole acts as a sink (production well) for porepressure > borehole pressure, and does nothing otherwise. If negative the borehole acts as a source (injection well) for porepressure < borehole pressure, and does nothing otherwise. The flow rate to/from the borehole is multiplied by |character|, so usually character = +/- 1, but you can specify other quantities to provide an overall scaling to the flow if you like.

• PorousFlowDictatorThe UserObject that holds the list of PorousFlow variable names

C++ Type:UserObjectName

Options:

Description:The UserObject that holds the list of PorousFlow variable names

• unit_weight(fluid_density*gravitational_acceleration) as a vector pointing downwards. Note that the borehole pressure at a given z position is bottom_p_or_t + unit_weight*(q - q_bottom), where q=(x,y,z) and q_bottom=(x,y,z) of the bottom point of the borehole. The analogous formula holds for function_of=temperature. If you don't want bottomhole pressure (or temperature) to vary in the borehole just set unit_weight=0. Typical value is = (0,0,-1E4), for water

C++ Type:libMesh::VectorValue

Options:

Description:(fluid_density*gravitational_acceleration) as a vector pointing downwards. Note that the borehole pressure at a given z position is bottom_p_or_t + unit_weight*(q - q_bottom), where q=(x,y,z) and q_bottom=(x,y,z) of the bottom point of the borehole. The analogous formula holds for function_of=temperature. If you don't want bottomhole pressure (or temperature) to vary in the borehole just set unit_weight=0. Typical value is = (0,0,-1E4), for water

• SumQuantityUOUser Object of type=PorousFlowSumQuantity in which to place the total outflow from the line sink for each time step.

C++ Type:UserObjectName

Options:

Description:User Object of type=PorousFlowSumQuantity in which to place the total outflow from the line sink for each time step.

• bottom_p_or_tFor function_of=pressure, this parameter is the pressure at the bottom of the borehole, otherwise it is the temperature at the bottom of the borehole

C++ Type:double

Options:

Description:For function_of=pressure, this parameter is the pressure at the bottom of the borehole, otherwise it is the temperature at the bottom of the borehole

• variableThe name of the variable that this kernel operates on

C++ Type:NonlinearVariableName

Options:

Description:The name of the variable that this kernel operates on

• point_fileThe file containing the coordinates of the points and their weightings that approximate the line sink. The physical meaning of the weightings depend on the scenario, eg, they may be borehole radii. Each line in the file must contain a space-separated weight and coordinate, viz r x y z. For boreholes, the last point in the file is defined as the borehole bottom, where the borehole pressure is bottom_pressure. If your file contains just one point, you must also specify the line_length and line_direction parameters. Note that you will get segementation faults if your points do not lie within your mesh!

C++ Type:std::string

Options:

Description:The file containing the coordinates of the points and their weightings that approximate the line sink. The physical meaning of the weightings depend on the scenario, eg, they may be borehole radii. Each line in the file must contain a space-separated weight and coordinate, viz r x y z. For boreholes, the last point in the file is defined as the borehole bottom, where the borehole pressure is bottom_pressure. If your file contains just one point, you must also specify the line_length and line_direction parameters. Note that you will get segementation faults if your points do not lie within your mesh!

### Required Parameters

• function_ofpressureModifying functions will be a function of either pressure and permeability (eg, for boreholes that pump fluids) or temperature and thermal conductivity (eg, for boreholes that pump pure heat with no fluid flow)

Default:pressure

C++ Type:MooseEnum

Options:pressure temperature

Description:Modifying functions will be a function of either pressure and permeability (eg, for boreholes that pump fluids) or temperature and thermal conductivity (eg, for boreholes that pump pure heat with no fluid flow)

• line_direction0 0 1Line direction. Note this is only used if there is only one point in the point_file.

Default:0 0 1

C++ Type:libMesh::VectorValue

Options:

Description:Line direction. Note this is only used if there is only one point in the point_file.

• use_mobilityFalseMultiply the flux by the fluid mobility

Default:False

C++ Type:bool

Options:

Description:Multiply the flux by the fluid mobility

• mass_fraction_componentThe index corresponding to a fluid component. If supplied, the flux will be multiplied by the nodal mass fraction for the component

C++ Type:unsigned int

Options:

Description:The index corresponding to a fluid component. If supplied, the flux will be multiplied by the nodal mass fraction for the component

• fluid_phase0The fluid phase whose pressure (and potentially mobility, enthalpy, etc) controls the flux to the line sink. For p_or_t=temperature, and without any use_*, this parameter is irrelevant

Default:0

C++ Type:unsigned int

Options:

Description:The fluid phase whose pressure (and potentially mobility, enthalpy, etc) controls the flux to the line sink. For p_or_t=temperature, and without any use_*, this parameter is irrelevant

• use_relative_permeabilityFalseMultiply the flux by the fluid relative permeability

Default:False

C++ Type:bool

Options:

Description:Multiply the flux by the fluid relative permeability

• use_internal_energyFalseMultiply the flux by the fluid internal energy

Default:False

C++ Type:bool

Options:

Description:Multiply the flux by the fluid internal energy

• well_constant-1Usually this is calculated internally from the element geometry, the local borehole direction and segment length, and the permeability. However, if this parameter is given as a positive number then this number is used instead of the internal calculation. This speeds up computation marginally. re_constant becomes irrelevant

Default:-1

C++ Type:double

Options:

Description:Usually this is calculated internally from the element geometry, the local borehole direction and segment length, and the permeability. However, if this parameter is given as a positive number then this number is used instead of the internal calculation. This speeds up computation marginally. re_constant becomes irrelevant

• re_constant0.28The dimensionless constant used in evaluating the borehole effective radius. This depends on the meshing scheme. Peacemann finite-difference calculations give 0.28, while for rectangular finite elements the result is closer to 0.1594. (See Eqn(4.13) of Z Chen, Y Zhang, Well flow models for various numerical methods, Int J Num Analysis and Modeling, 3 (2008) 375-388.)

Default:0.28

C++ Type:double

Options:

Description:The dimensionless constant used in evaluating the borehole effective radius. This depends on the meshing scheme. Peacemann finite-difference calculations give 0.28, while for rectangular finite elements the result is closer to 0.1594. (See Eqn(4.13) of Z Chen, Y Zhang, Well flow models for various numerical methods, Int J Num Analysis and Modeling, 3 (2008) 375-388.)

• line_length0Line length. Note this is only used if there is only one point in the point_file.

Default:0

C++ Type:double

Options:

Description:Line length. Note this is only used if there is only one point in the point_file.

• use_enthalpyFalseMultiply the flux by the fluid enthalpy

Default:False

C++ Type:bool

Options:

Description:Multiply the flux by the fluid enthalpy

### Optional Parameters

• drop_duplicate_pointsTrueBy default points added to a DiracKernel are dropped if a point at the same locationhas been added before. If this option is set to false duplicate points are retainedand contribute to residual and Jacobian.

Default:True

C++ Type:bool

Options:

Description:By default points added to a DiracKernel are dropped if a point at the same locationhas been added before. If this option is set to false duplicate points are retainedand contribute to residual and Jacobian.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Default:False

C++ Type:bool

Options:

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.