Geology Reference
In-Depth Information
Initial head distribution: 0 m
Initial head value at the inlet face: + 5 m
Initial head value at the outlet face: - 5 m
Duration of the simulation: two days
Equivalent Transmissivity
The results of the tests are obtained for the two directions. They are obtained
as the averaged value of the results produced by five equi-consistent networks,
in a statistic sense. The five independent responses for a cell of 50 m × 50
m × 30 m for case 4 are listed hereafter:
Table 3:
Flow in X and Y directions based on the parameters
used for calibrating the slug test model in Table 2
Alternative
Seed number
Flow in X direction
Flow in Y direction
(l/s)
(l/s)
1
7571
2.76
3.49
2
3317
2.25
2.66
3
4531
2.31
3.04
4
9999
2.35
2.59
5
5703
1.92
2.91
Mean Value
-
2.32
2.93
From the calculated mean flux value combined with the geometry of the
block and the applied head gradient, we derive an equivalent horizontal
transmissivity, for both directions.
Because the cell has a square shape, the transmissivity is directly given
when dividing the flux, expressed in m
3
s
-1
by the head difference, expressed
in m. In the East-West direction (resp. along X axis), we obtain
T
XX
= 2.3
× 10
-4
m
2
s
-1
and in the North-South direction (resp. along Y axis), we obtain
T
YY
= 2.94 × 10
-4
m
2
s
-1
. Therefore the equivalent porous media is likely to
be slightly anisotropic, with a factor
T
XX
/
T
YY
close to 0.8. An equivalent
isotropic horizontal permeability would be about 8.7 × 10
-5
ms
-1
. For case
5, there is no connection at a big scale,
T
= 0.
Equivalent Storativity
To derive an equivalent storativity factor suitable for hydraulic calculations
at the regional scale, the calibrated fracture storativities are combined, using
the densities of the fracture sets as weighting factors.
Table 2 shows that, to fit the data, the storativities values for the horizontal
fracture set are smaller than the one for the sub-vertical and vertical fracture
set. This can be due to the fact that because of the geometry, the vertical
fractures are more in unconfined condition than the horizontal ones. In that
case, the storativity calculated for the vertical and horizontal fracture set is
