9 THE P RECORDS

The P records, like the M records, are read by the main routine. Here, however, the input is identified by its function (plotting) rather than by the routine from which it is read. Plotting, within the SWIFT model, is identified with well data in that pressure, temperature and brine concentrations, both at the surface and at the bottom-hole, may be plotted as functions of time. Table 9-1 exhibits the various dependent variables which may be plotted as functions of the well characteristics. Plots for an observation well are particularly useful since they simply indicate the behavior of the grid-block variables as functions of time.

In order to facilitate model calibrations, printer plots are used. The time axis is always directed down the page with range and resolution determined by the input parameters. The dependent-variable axes, on the other hand, are always directed across the page. Here the range is determined externally by the input parameters, but the resolution is fixed internally in that the specified range is divided into 100 columns in each case. The plotting symbols which are used are given in Table 9-2. If there are several values of the dependent variables within the prescribed resolution on the time scale, then the average value is plotted. If there are no such values, then, of course, no values are plotted.

Calculated plot data is stored by the code on UNIT 12. If plots are desired for a previous run, then UNIT 12 should be attached.

If NPLP = 0, NPLT = 0, and NPLC = 0, (i.e., no plots are desired), skip all P records.

The plotting data for one well consist of the data from READ P-2 through READ P-4. Enter as many sets of these data as there are wells for which plots are desired. If plots are desired for all the wells enter NWT sets of these data. If less than NWT sets are entered, then follow the last set with a blank record to end the input of plotting data.

Table 9-1. Dependent plotting variables versus well characteristics.

		Plotting Variables^2,3
Well Type	Point of Specification¹	Bottom-Hole	Surface
Observation⁴	--	P, T, C
Injection	Bottom-Hole	P
Injection	Surface	P, T	P
Production	Bottom-Hole	P, T, C
Production	Surface	P, T, C	P, T

^{1 The point of specification
is controlled by integer ISURF (READ M-2), i.e., ISURF = 0 for bottom-hole
conditions and ISURF = 1 for surface conditions.}

^{2 Notation here
is consistent with that of Reeves et al. [1986a], i.e.,}

^{P - pressure,}

^{T - temperature,}

^{C - brine concentrations.}

^{3 The list of plotting
variables given here assumes that NCALL = 0 (READ M-2).}

^{4 An observation
well is defined by the flow rate, Q = 0.}

^{Table 9-2. Plotting symbols.}

Symbol	Data Type
X	Calculated
O	Observed
*	Coincident Calculated and Observed

READ P-2 (I5, 5X, 10A4) Well Identity.

LIST: KW, ID
KW The well number.

ID A title to the plots for well number KW.

READ P-3 (7E10.0) Variable Ranges and Resolutions. LIST: TMN, TMX, D1, PWMN, PWMX, PSMN, PSMX, TWMN, TWMX, TSMN, TSMX, CMN, CMX
TMN Lower limit on time, d (s).

TMX Upper limit on time, d (s).

D1 Time step for each row, d (s).

The three parameters immediately above determine the number of rows, NROWS, to be used, i.e., NROWS = (TMX - TMN)/D1. Current fixed dimensions restrict this quantity to NROWS # 400.
If D1 is set to zero, a default value is calculated assuming 50 rows, i.e., D1 = (TMX - TMN)/50.

PWMN, Lower limits on bottom-hole pressure, psi

PSMN, (Pa); face pressure, psi (Pa); bottom-hole TWMN, temperature, EF (EC); surface temperature, EF TSMN, (EC); and brine concentration, dimensionless, CMN respectively. PWMX, Upper limits on bottom-hole pressure, psi. PSMX (Pa); surface pressure, psi (Pa); bottom-hole TWMX, TSMX, CMX temperature, FE (EC); surface temperature, EF (EC); and brine concentration, dimensionless, respectively. If there are no observed data, then enter any negative number in the first field of the following record. Fixed dimensions limit the number of values for any one variable to 300 or less. If there are such data, then enter up to 300 (inclusive) of these records in the read set below, and terminate the read with any negative number in the first field.

READ P-4 (6E10.0) Observed Data.

Read as many records (up to 300) as there are observed data points (one record for each value of time at which the observed values are available). Follow the last record with a negative number in the first field specification (E10.0).

LIST: TOX, POW, POS, TOW, TOS, COC
TOX Observation time, d (s).

POW Bottom-hole pressure, psi (Pa).

POS Surface pressure, psi (Pa).

TOW Bottom-hole temperature, EF (EC).

TOS Surface temperature, EF (EC).

COC Brine concentration, dimensionless.