This command selects as a parameter the skin zone radius around a well. In general, the radial thickness of the skin zone is predefined by the discretization of the flow region. In order to estimate the skin zone radius, the TOUGH2 mesh must be generated using the MESHMAKER utility. Furthermore, two zones must be generated using logarithmically increasing radial distances (option LOGAR). The skin radius is defined by the parameter RLOG after the first appearance of keyword LOGAR. In addition, an I5 integer must be provided after NRAD, NEQU, and NLOG, indicating the material type number for the corresponding grid blocks (see example below). Estimation of a skin zone radius may be unstable if changing the discretization significantly affects the modeling results.
The following MESHMAKER block is from a TOUGH2 input file. A radial mesh is
generated with a borehole of radius 0.1 m (material type 1), a skin zone of material type 2
and initial radius of 0.3 m, partitioned into 20 grid blocks, and an outer zone of material type
3 which extends to a radial distance of 10.0 m. The thickness of the layer is 1.0 m.
20 2 0.300E+00 0.100E-01
80 3 1.000E+01
The corresponding parameter block in the iTOUGH2 input file reads:
> PARAMETER See Also
>> SKIN zone radius
>>> MATERIAL: SKINZ (= material name 2 in block ROCKS)
>>>> ANNOTATION: Skin radius
>>>> initial guess: 0.3
>>>> RANGE : 0.12 1.00
Page updated: July 29, 1997