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Unformatted text preview: they vary along the length of the
open interval of the well (in which case any negative value should be specified above and the actual values then specified
for each node or open interval in dataset 2d below). For example, if Rw = 1, then it is assumed that Rw varies along the
length of the well and a real value of Rw must be defined for each node (or open interval) of this well in dataset 2d. Table A1–1. Summary of parameter definition requirements for available wellloss options.
Losstype
NONE
THIEM
SKIN
GENERAL
SPECIFYcwc Parameter definition requirements for datasets 2c and (or) 2d
RW
—
√
√
√
— Rskin
—
—
√
—
— Kskin
—
—
√
—
— B —
—
—
√
— C —
—
—
√
— P —
—
—
√
— CWC
—
—
—
—
√ For each node (or open interval) of this well the user must use either input format 1 or input format 2; in either case,
dataset 2d must have │NNODES│ records: Input format 1, for NNODES > 0
2d1. Data: LAY ROW COL {Rw Rskin Kskin B C P CWC PP} Input format 2, for NNODES < 0
2d2. Data: Ztop Zbotm ROW COL {Rw Rskin Kskin B C P CWC PP}
LAY, ROW, COL
are the layer, row, and column numbers of each model cell (node) for the current well. If
NNODES > 0, then a total of NNODES model cells (nodes) must be specified for each well
(and dataset 2d must contain NNODES records). In the list of nodes defining the multinode
well, the data list must be constructed and ordered so that the first node listed represents
the node closest to the wellhead, the last node listed represents the node furthest from the
wellhead, and all nodes are listed in sequential order from the top to the bottom of the well
(corresponding to the order of first to last well nodes). A particular node in the grid can be
associated with more than one multinode well.
Ztop, Zbotm are the top and bottom elevations of the open intervals (or screened intervals) of a vertical well.
These values are only read if NNODES < 0 in dataset 2a. The absolute value of NNODES
indicates how many open intervals are to be defined, and so must correspond exactly to the
number of records in dataset 2d for this well. In the list of intervals defining the multinode
well, the data list must be constructed and ordered so that the first interval listed represents
the shallowest one, the last interval listed represents the deepest one, and all intervals are
listed in sequential order from the top to the bottom of the well. If an interval partially or fully
intersects a model layer, then a node will be defined in that cell. If more than one open interval
intersects a particular layer, then a lengthweighted average of the celltowell conductances Appendix 1—Data Input Instructions for MultiNode Well (MNW2) Package 49 will be used to define the wellnode characteristics; for purposes of calculating effects of
partial penetration, the cumulative length of well screens will be assumed to be centered
vertically within the thickness of the cell. If the well is a singlenode well by definition of
LOSSTYPE = NONE and the defined open interval straddles more than one model layer, then
the well will be associated with the cell where the center of the open interval exists.
LOSSTYPE variables if the relevant variables were set to a negative value in dataset 2c, then that means that they
vary in value among nodes (or open intervals, if NNODES < 0) and should be defined here
in dataset 2d according to the definitions given under dataset 2c. Which values are specified
here, if any, depends on which were set to a negative value in dataset 2c.
PP is the fraction of partial penetration for this cell (see PPFLAG in dataset 2b). Only specify if
PPFLAG > 0 and NNODES > 0. Note 5: If NNODES < 0 and elevations indicate multiple well screens or open intervals within a single model layer, then the
model will assign a single equivalent composite well screen for the node based on the ratio of the screen length to layer
thickness (see additional discussion in text). However, if CWC values are specified explicitly by the user, then it is assumed
that these values are already appropriate for the actual length of screen and are not further adjusted by this ratio (that is,
equation 37 is not applied). If PUMPLOC ≠ 0:
2e. Data: {PUMPLAY PUMPROW PUMPCOL} {Zpump}
PUMPLAY, PUMPROW, and PUMPCOL are the layer, row, and column numbers, respectively, of the cell (node) in
this multinode well where the pump intake (or outflow) is located. The location defined
in dataset 2e should correspond with one of the nodes listed in 2d for this multinode well.
These variables are only read if PUMPLOC > 0 in 2b.
Zpump is the elevation of the pump intake (or discharge pipe location for an injection well). Zpump is
read only if PUMPLOC < 0; in this case, the model assumes that the borehole is vertical and
will compute the layer of the grid in which the pump intake is located. Note 6: If the intake location (or discharge point for an injection well) is specified by node and that node does not correspond
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This document was uploaded on 01/20/2014.
 Winter '14

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