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

MATCH PARAMETERS
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10 PSI
150 t 1 Ohr
PO 0.079
FT
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+ DATA
- SIMULATION
+PUMP OFF
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to 5/6/83 1O:OO
I I I
100
0 200 400 600 800 100
ELAPSED TIME, hours
Figure 5-79. DOE-l/Culebra Pumping Test Linear-Linear Sequence Plot with INTERPRET Simulation
Drawdown responses probably related to the DOE-1
pumping were noted at wells H-3, H-1, P-17, and
possibly H-4 during routine water-level monitoring.
Because these responses were not anticipated,
however, no pre-test baseline water-level monitoring
had been performed at these wells. Consequently,
the presence or absence of pre-existing water-level
trends and water levels precisely at the beginning of
DOE-1 pumping are not defined. In addition, well H-
4c was being pumped for a tracer test during all
phases of the DOE-1 pumping test, which may have
influenced some of the water levels observed.
Because of these uncertainties concerning the
observed water-level data, the observation-well
"responses" were not interpreted.
5.2.2.22 Engle. The Engle well was pumped for a
period of 165.5 hr beginning November 4, 1983, to
collect water-quality samples. The pumping rate was
held at a nearly constant 9.8 gpm for approximately
the first 97 hr of pumping. Pressure-drawdown data
collected over this period are amenable to
interpretation. Recovery data were collected for only
one hr after the pump was turned off, producing
nothing useable for interpretation. A more complete
description of this test and the test data are
contained in Stensrud et at. (1987).
Figure 5-80 shows a log-log plot of the Engle
drawdown data, along with simulations of the data
generated by INTERPRET. Late-time scatter of the
data, particularly of the pressure-derivative data, is
probably related to pumping-rate fluctuations. The
model used for the simulations is representative of a
single-porosity medium with a transmissivity of
43 ftz/day (Table 5-3). Assuming a Culebra porosity
of 20%, a total-system compressibility of 1.0 x
10-5 psi-1, and a fluid viscosity of 1.0 cp, the skin
factor for this simulation is about 4.2. A
dimensionless Homer plot of the drawdown data,
along with a simulation generated using the same
model, is shown in Figure 5-81. Again, the
simulation matches the test data well until the data
scatter at late time, indicating that an appropriate
model was selected.
106