AQUIFER_DATA

Defines a radial or linear aquifer, modelled accordingly to [CT+60]. AQUIFER_DATA must be followed by a name for the aquifer. For example:

AQUIFER_DATA A1
  BACKFLOW
  DEPTH     2550.0 m
  THICKNESS 100 m
  RADIUS    507.8 m
  PERM      500  mD
  COMPRESSIBILITY 2.0E-9 1/Pa
  POROSITY  0.1
  VISCOSITY 1 cP
  CONN_D 1 1 1 9 1 1 X-
  CONN_D 1 9 1 1 1 1 Y-
END

It is possible to connect the same aquifer to more grid blocks; connections can be added by multiple lines within the definition of one aquifer (see the multiple CONN_D lines above).

The options supported by AQUIFER_DATA are:

BACKFLOW

Specifies that fluids are allowed to migrate from the reservoir to the aquifer.

This option should be used with caution, as it can result in unwanted fluid re-circulations between grid blocks connected to the same aquifer. As a general rule an aquifer should be far away from the main injection/production regions.

DEPTH

Specify aquifer depth. Units are required.

ZAQUIFER

Specify aquifer elevation. For example if the aquifer depth is 2500 m, ZAQUIFER will be -2500 m. Units are required.

THETA_FRACTION, THETA

Specify the aquifer angle (for a radial aquifer). Defaulted to a THETA_FRACTION of 1.0. THETA allows the same data to be added as an angle in degrees - .e.g. THETA 145.

So THETA_FRACTION = THETA/360.0

THICKNESS

Aquifer thickness. Required. Units must be specified.

WIDTH

Aquifer width, required for linear aquifer. Units must be specified.

RADIUS

Aquifer inner radius. Required for radial aquifer. Units must be specified.

PORO, POROSITY

PORO or POROSITY defines the aquifer porosity. Required.

PERM, PERMEABILITY

PERM or PERMEABILITY defines the aquifer permeability. Units must be specified. Required

CMPR, COMPRESSIBILITY

Aquifer compressibility (rock + water): required.

PINIT, PRESSURE

PINIT or PRESSURE defines the aquifer pressure. Pressure units must be specified. Not required, if not entered the aquifer pressure will be set in equilibrium with reservoir.

TINIT, TEMPERATURE

TINIT or TEMPERATURE defines the aquifer temperature. Temperature units must be specified.

Required for thermal runs.

GAS_IN_LIQUID_MOLE_FRACTION

Gas in liquid mole fraction in brine. Defaults to 0.0. Only used in GW mode.

IFT

Influence function table. Not required. If omitted, defaults to infinite aquifer.

Example:

IFT
   0.01 0.112
   0.05 0.229
   0.10 0.315
   0.15 0.376
   0.20 0.424
   0.25 0.469
   0.30 0.503
   0.40 0.564
   0.50 0.616
   0.60 0.659
   0.70 0.702
   0.80 0.735
   0.90 0.772
   1.00 0.802
   1.50 0.927
   2.0  1.020
   2.5  1.101
   3.0  1.169
   4.0  1.275
   5.0  1.362
   6.0  1.436
   7.0  1.500
   8.0  1.556
   9.0  1.604
   10.0 1.651
   15.0 1.829
   20.0 1.960
   25.0 2.067
   30.0 2.147
   40.0 2.282
   50.0 2.388
   60.0 2.476
   70.0 2.550
   80.0 2.615
   90.0 2.672
  100.0 2.723
  150.0 2.921
  200.0 3.064
  250.0 3.173
  300.0 3.263
  400.0 3.406
  500.0 3.516
  600.0 3.608
  700.0 3.684
  800.0 3.750
  900.0 3.809
 1000.0 3.860
END IFT

CONN_D

Specifies blocks of connections to attach aquifer to reservoir cell faces. Follows the ECLIPSE grdecl convention (K index is counted downwards from the top layer).

An example is:

CONN_D 1 9 9 9 1 1 Y+

Note that the connection box argument order is:

CONN_D IL IU JL JU KL KU

Where:

  • IL and IU are a range of cell indices in the I-direction

  • JL and JU are a range of cell indices in the J-direction

  • KL and KU are a range of cell indices in the K-direction

Connections will be made to cells with I-indices such that \(I \geq IL\) and \(I \leq IU\), etc.

The cell faces to attach the aquifer are specified by one of the following options:

  • X+ or I+, faces connecting cells with I-indices to cells with (I+1)-indices

  • Y+ or J+, faces connecting cells with J-indices to cells with (J+1)-indices

  • Z+ or K+, faces connecting cells with K-indices to cells with (K+1)-indices

The pairs (X- or I-), (Y- or I-) and (Z- or K-) follow the same logic, and are used to connect to cells with (I-1)-indices, (J-1)-indices and (K-1)-indices.

A number of CONN_D sub-keywords may be entered to build up the full connection. If the same face of the same cell is included more than once, only one connection will be generated.

CONN_Z

Warning: keyword to be used only by proficient PFLOTRAN users. Unless there is some specific reason, consider using CONN_D instead.

Specifies blocks of connections to attach aquifer to reservoir cell faces.

CONN_Z use the convention that the K index is counted upwards from the bottom layer. For example:

CONN_Z 1 9 9 9 1 1 Y+

Note that the connection box argument order is:

CONN_Z IL IU JL JU KL KU

Where:

  • IL and IU are a range of cell indices in the I-direction

  • JL and JU are a range of cell indices in the J-direction

  • KL and KU are a range of cell indices in the K-direction

Connections will be made to cells with I-indices such that \(I \geq IL\) and \(I \leq IU\), etc.

The cell faces to attach the aquifer are specified by one of the following options:

  • X+ or I+, faces connecting cells with I-indices to cells with (I+1)-indices (GRDECL grid format).

  • Y+ or J+, faces connecting cells with J-indices to cells with (J+1)-indices (GRDECL grid format).

  • Z+ or K+, faces connecting cells with K-indices to cells with (K+1)-indices (K index counted upwards from the bottom layer).

The pairs (X- or I-), (Y- or I-) and (Z- or K-) follow the same logic, and are used to connect to cells with (I-1)-indices, (J-1)-indices and (K-1)-indices.

When using CONN_Z, the top faces of a reservoir with 100 layers are defined with Z+. See the following example:

CONN_Z  1 50 1 50  100 100  Z+