Sets up an observation point(s) within the problem domain.
OBSERVATION REGION <region_name> VELOCITY AT_CELL_CENTER AT_COORDINATE END
<region_name>: the name of a region specified in the input deck, (i.e. a point or an array of points within the reservoir domain) where the observation is placed.
VELOCITY: if included prints the cell centered velocities for the cells being observed
AT_CELL_CENTER: if included specifies that the observation data is sampled at center of cell intersected by observation (default).
AT_COORDINATE: if included the observation data is interpolated (linearly) from neighboring cell centers to coordinate
See example below:
OBSERVATION REGION inj1 /