TOIL_IMS Equilibration

FLOW_CONDITION can be used to set up a hydrostatic equilibration that defines a distribution for pressure, saturation and temperature versus depth. Such a condition can be applied to the entire reservoir to initialize a study when used within INITIAL_CONDITION. See example below:

FLOW_CONDITION equilibration_toil
  TYPE
    PRESSURE HYDROSTATIC
  /
  PRESSURE 327.0 Bar
  RTEMP 50 C
  DATUM_D 2430.0 m
  OWC_D 2470.0 m
  PCOW_OWC 0.5 Bar
/

The input sub-cards supported by the TOIL_IMS equilibration are:

DATUM_D

Depth of the reference datum. Requires units. Defaults to 0.

PRESSURE

Reference pressure at datum. Must be entered or the code will return an error. Pressure units must be specified.

OWC_D

Defines the depth of the oil-water phase contact. Requires units. If not set defaults to 0

PCOW_OWC

Defines the capillary pressure between the water and the oil phases at the depth of the oil-water phase contact. It requires pressure units. If not set defaults to 0.

RTEMP

Constant temperature value to assign to the reservoir. Note that currently only degrees Celsius are accepted, for any other temperature unit the software returns an error. RTEMP is an alternative to TEMPERATURE_TABLE, either one or the other can be supplied.

TEMPERATURE_TABLE

Define the temperature versus depth for all grid blocks associated with the hydrostatic equilibration. See example below:

TEMPERATURE_TABLE
  D_UNITS m
  TEMPERATURE_UNITS C
  RTEMPVD
    2300.0 126.0
    2400.0 128.0
  /
END

Units must be defined using D_UNITS and TEMPERATURE_UNITS. The data depth vs temperature are entered within the RTEMPVD block. The entries must be ordered for monotonically growing depths, and at least two entries are required for the internal interpolation to work.

If the TEMPERATURE_TABLE is defined RTEMP cannot be supplied at the same time in the same flow condition, otherwise the code returns an error, as the temperature is ambiguously defined. To remove the RTEMPVD table, the entire TEMPERATURE_TABLE block must be removed. If only the RTEMPVD table is removed leaving the TEMPERATURE_TABLE block, the code returns an error as a RTEMPVD table is expected.

NUM_EQUIL_NODES

Defines the number of nodes used in the internal hydrostatic equilibration calculation. Below is an example:

FLOW_CONDITION equilibration_toil
  TYPE
    PRESSURE HYDROSTATIC
  /
  PRESSURE 327.0 Bar
  RTEMP 50 C
  DATUM_D 2430.0 m
  OWC_D 2470.0 m
  PCOW_OWC 0.5 Bar
  NUM_EQUIL_NODES 2001
/

The reservoir vertical extension is divided into (NUM_EQUIL_NODES – 1) equispaced depth intervals, and the one-dimensional grid obtained is used to carry out the hydrostatic equilibration calculation. If not entered, NUM_EQUIL_NODES defaults to 501. In some cases it might be beneficial to test higher resolutions than the default one to get a more accurate initial state.