OBSERVATION_FILE

The OBSERVATION_FILE sub-block of OUTPUT requests that the simulation outputs observations of variables on limited portions of the reservoir domain. See example below:

OUTPUT
  FORMAT HDF5
  MASS_BALANCE_FILE
    PERIODIC TIMESTEP 1
  END
  OBSERVATION_FILE
     PERIODIC TIMESTEP 5
      VARIABLES
         TEMPERATURE
         GAS_SATURATION
         GAS_PRESSURE
      END
  END
END

OBSERVATION_FILES output observation point variables into ASCII files named <input_deck_name>-obs-proc_numb.tec, where proc_numb is the processor number the observation points belong to. Due to the domain decomposition, different observation points can fall within different sub-domains. The simulator outputs one observation file for each sub-domain, with all variable information related to the observation points falling within that sub-domain. Within each observation file, the variable values of all observation points are listed one time step for each line, and within each line the variables requested are grouped and printed by observation point.

See below an example of an an observation file for a single observation point for which temperature, gas saturation and gas pressure are printed:

../../_images/obs_file_example.png

The options supported for OBSERVATION_FILE are:

TIMES

The TIMES sub-block of OBSERVATION_FILE takes one argument that specifies a time unit, followed by a generic number N of arguments that are the times for which the observation point variables are output. See example:

OBSERVATION_FILE
   TIMES d 5 30 100 500 1095
END

PERIODIC TIMESTEP

The PERIODIC TIMESTEP sub-block of OBSERVATION_FILE takes one argument, which is the number of time steps between two consecutive simulation states, for which observation point variables are output. See example:

OBSERVATION_FILE
  PERIODIC TIMESTEP  1
END

PERIODIC TIME

The PERIODIC TIME sub-block of OBSERVATION_FILE takes two arguments: the first is the time between two consecutive simulation states for which observation point variables are output, the second is the time unit, see example below:

OBSERVATION_FILE
  PERIODIC TIME  5 d
END

VARIABLE

The VARIABLE sub-block of OBSERVATION_FILE is a multiple-line instruction block, starting with the keyword VARIABLE and ending by END or ‘/’.

The variables that can be output are model-dependent. Below a the list of variables available for TOWG and TOIL_IMS grouped by fluid phase and material properties, using the syntax expected within by the VARIABLE block:

  • OIL_PRESSURE, OIL_SATURATION, OIL_DENSITY, OIL_MOBILITY, OIL_ENERGY

  • GAS_PRESSURE, GAS_SATURATION, GAS_DENSITY, GAS_MOBILITY, GAS_ENERGY

  • LIQUID_PRESSURE, LIQUID_SATURATION, LIQUID_DENSITY, LIQUID_MOBILITY, LIQUID_ENERGY

  • TEMPERATURE, POROSITY, PERMEABILITY_X, PERMEABILITY_Y, PERMEABILITY_Z

Note that the GAS variables are available only for the TOWG flow model, and that LIQUID refers to water. Each variable to print must be included in a single line.

If no VARIABLES are specified, the flow model default set of variables will be printed.