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

P-15 was bailed on four occasions in March and April
1987 (Section 3.17) to develop the hydraulic
connection between the perforated casing and the
formation. In May 1987, two falling-head slug tests of
the Culebra were performed. The first was initiated
on May 16, and the second began on May 19. A
semilog plot of the data from the first test is
presented in Figure 5-67, along with the best-fit typecurve
match. This match provides a transmissivity
estimate of 0.090 ft*/day (Table 5-3). The semilog
plot of the data from the second test (Figure 5-68)
shows a fit to the same type cuwe, but with a slightly
different time match. The transmissivity estimate
from this match is 0.092 ft2/day (Table 5-3). These
values are in excellent agreement, and are only
slightly higher than the transmissivity value of
0.07 ft2/day reported by Mercer (1983) for the
Culebra at P-15.
5.2.2.17 P-17. Mercer (1 983) reported the
transmissivity of the Culebra at P-17 to be 1.0 ftYday,
based on a slug test conducted by the USGS. P-17
was retested in November 1986 after the hydraulic
head and fluid density of the Culebra at that location
proved difficult to simulate with the existing data in
an areal modeling exercise (Haug et al., 1987).
To verify the transmissivity of the Culebra at P-17, two
falling-head slug tests were performed. The first test
was initiated on November 20, 1986, and lasted
nearly 22 hr, by which time 99% of the induced
pressure differential had dissipated. Figure 5-69
shows a semilog plot of the falling-head slug-test
data, along with the best-fit type curve. This fit
provides a transmissivity estimate of 1 .O ftzlday
(Table 5-3), which is the same value reported by
Mercer (1983). The second test was begun on
November 24, 1986, and lasted about 19 hr. A
semilog plot of the data from the second test and the
best-fit type-curve match are shown in Figure 5-70.
The type-curve match for the second test is very
similar to that used for the first test, and provides a
second transmissivity estimate of 1 .O ft2/day
(Table 5-3). The slight difference between the test
data and the type curve at early time is probably due
to the packer used in the test (Figure 3-19)
continuing to deflate, and thus changing the wellbore
volume, during the first few minutes of the test. The
fluid-pressure data collected during the P-17 slug
tests are reported in Stensrud et al. (1987).
5.2.2.18 P-18. Mercer (1983) reported the
transmissivity of the Culebra at P-18 to be
0.001 ft*/day based on a bailing test conducted by
the USGS in 1977 (Mercer and Orr, 1979). This
estimate of transmissivity was uncertain, however,
because of the low degree of recovery obtained
during the test. To evaluate the possibility that the
low apparent transmissivity might be related to a
poor hydraulic connection between the well and the
formation, the Culebra interval in P-18 was
reperforated (Section 3.18), a PIP was set in the well
on 2.375-inch tubing to decrease the wellbore
volume in communication with the Culebra, the
tubing was bailed on two occasions to develop the
well, and a rising-head slug test was performed.
The tubing was bailed for the last time on August 26,
1987, lowering the Culebra water level from about
543 ft to about 842 ft deep (Stensrud et al., 1988).
On September 10, 1987, the water level had
recovered to a depth of about 734 ft, and
a minipacker with a feedthrough plug and attached
pressure transducer was installed and inflated in the
tubing at a depth of about 781 ft (Figure 3-20). The
fluid-pressure buildup beneath the minipacker in
response to the bailing was monitored with a
transducer until November 6,1987, by which time the
pressure recovery had slowed to an erratic rate of
about 0.1 psi/day. A rising-head slug test was
initiated on November 6, 1987 by deflating
the minipacker and removing it from the tubing, after
which the rise in the P-18 water level was monitored
for several months. The fluid-pressure and waterlevel
data collected during the development and
testing of P-18 will be reported in Stensrud et al. (in
preparation).
The pretest stabilized formation pressure and the
initial slug-test pressure at P-18 were measured by
the transducer attached to the feedthrough plug in
the minipacker in the tubing. These pressures were
converted to water levels to allow interpretation of
the water levels measured during the slug test.
When the tubing was bailed on August 26,1987, the
fluid removed had a specific gravity of about 1.05.
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