This command selects as a parameter a constant used to shift the calculated TOUGH2 output. The constant is added to the output that refers to a specific data set:
z = zTOUGH2 + shift
where shift is the constant added to the calculated TOUGH2 output zTOUGH2 . The result z is compared to the measurement z* of the corresponding data set. This option allows removal of a constant from the data. For example, if matching relative pressure data that fluctuate around an unknown mean, or if a flowmeter exhibits an unknown offset that needs to be estimated, the shift parameter being estimated is the mean or offset, respectively. A non-zero value must be provided as an initial guess through the iTOUGH2 input file using command >>>> GUESS. The data set is identified by number using command >>> SET (p) or command >>>> INDEX (p). If the constant is known, i.e. does not need to be estimated, use command >>>> SHIFT, a subcommand of > OBSERVATION, to shift the data.
>>> SET No. : 1
>>>> ANNOTATION: atmos. pres.
>>>> GUESS: -1.0E5 [Pa] subtract atmospheric pressure
>>>> ANNOTATION: offset
>>>> INDEX : 2 3 4 (one constant for data sets 2, 3, and 4)
>>>> GUESS : 4.0E-6 [kg/sec]