Beauheim 1987 - Waste Isolation Pilot Plant - U.S. Department of ...

was followed by a 92-minute FBU. The SFL lasted
about 32 minutes, and was followed by a SBU almost
16 hr long. To obtain equivalent constant-rate flow
periods, each of the flow periods was divided into
two shorter periods. The FFL was divided into two
periods with flow rates of 0.028 and 0.021 gpm, and
the SFL was divided into periods with flow rates of
0.022 and 0.017 gpm (Table 5-1). The slug test
lasted slightly over 6 hr, by which time about 57% of
the induced pressure differential had dissipated.
Overpressureskin effects were apparent during the
Forty-niner claystone testing, just as they were
during all other testing at H-14. The fluid pressure
reached a maximum of 67.9 psia during the initial
equilibration period, was essentially constant at
66.8 psia at the end of the FBU, and peaked at
66.2 psia during the SBU (Figure 5-95). The
superposition of pressure-skin effects manifested in
the Magenta test data (see Section 5.2.4.1) was not
apparent, however, in the Forty-niner claystone test
data.
Figure 5-96 shows a log-log plot of the Forty-niner
claystone FBU data with an INTERPRET-generated
simulation. The late-time pressure derivative shows
the decline indicative of overpressure skin. The
simulation is representative of a single-porosity
medium with a transmissivity of 7.1 x 10-2 ftzjday
(Table 5-2). Assuming a porosity of 30%, a totalsystem
compressibility of 1.0 x 10-5 psi-', and a fluid
viscosity of 1.0 cp, the skin factor for this simulation
is about 3.2, indicating a damaged well.
The dimensionless Horner plot of the FEU data is
shown in Figure 5-97. The simulation matches the
observed data very well until late time, when the data
deviate towards a static pressure lower than the
67.8 psia specified for the simulation. This
discrepancy between the observed data and the
10'
0
n
w'
a 3
v)
v)
w
a
n
2 100
W
4
2
2
v)
2
w
s
5
MATCH PARAMETERS
AP
= 1.0 psi
t
= 1.0 hr
PO = 0.21
tdc, = 120
Cge2. = 5000
**
0 PRESSURE DATA
* PRESSURE-DERIVATIVE DATA
- SIMULATIONS
10'
100 10' 102
DIMENSIONLESS TIME GROUP, tdC,
103
Figure 596. H-l4/Forty-Niner Claystone First Buildup Log-Log Plot with INTERPRET Simulation
120