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

1.0
0.9
0.8
0.7
0.6
0
0.5
0.4
0.3
0.2
0.1
0.0
10-3 10-2 lo-’ 1 00
ELAPSED TIME, hours
10’ 102
Figure 5-46. H-1 6/Culebra Slug-Test Plot
at 735.0 ft. Thus, the lower 2.7 ft of the Tamarisk and
the upper 3.6 ft of the unnamed lower member were
tested along with the Culebra. These overlying and
underlying intervals are composed of anhydrite,
gypsum, and/or clay, and were not considered to
have contributed significantly to the transmissivity
measured during the Culebra testing.
The H-17 Culebra testing was performed from
October 9 to 12, 1987. The testing consisted of two
DST flow periods, two buildup periods, and a risinghead
slug test (Figure 5-47). The FFL lasted about
16 minutes, and was followed by a 449- minute FBU.
The SFL lasted about 24 minutes, and was followed
by a 939-minute SBU. To obtain constant flow rates
for buildup analyses, the FFL was divided into two
flow periods having rates of 0.368 and 0.259 gpm,
and the SFL was divided into two flow periods having
rates of 0.443 and 0.280 gpm (Table 5-1). The slug
test lasted about 48 hr, by which time about 99% of
the induced pressure differential had dissipated.
The data from these tests are presented in Stensrud
et al. (1988).
A log-log plot of the FBU data is presented in
Figure 5-48, along with a simuiation generated by
INTERPRFT. The simulation is representative of a
single-porosity medium with a transmissivity of
0.21 ft*/day (Table 5-3). Assuming a Culebra porosity
of 20%, a total-system compressibility of 1.0 x
10-5 psi-’, and a fluid viscosity of 1.0 cp, the skin
factor for this simulation is -1.5, indicating a
moderately stimulated well. The decline in the
pressure derivative at late time indicates the
presence of an overpressure skin created during
coring and reaming of the Culebra October 7 and 8,
1987. The dimensionless Horner plot of the FBU
data (Figure 5-49) also shows the effects of the
overpressure skin as the data trend slightly upward
at very late time towards a pressure lower than the
145.5 psia specified as the static formation pressure
for that simulation. In fact, the buildup pressure
reached a maximum of 144.8 psia after 275 minutes
of the FBU (Figure 5-47), and declined slightly
thereafter. The data collected after the maximum
pressure was reached are not included on the
analysis plots.
82