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:
The options supported for OBSERVATION_FILE are:
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
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
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
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.