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

(or areal extent) of the aquifer one wishes to test.
Following the pumping period, the recovery (rise) of
the water level or pressure in the well is monitored,
typically for a period twice as long as the pumping
period.
Pumping tests were performed in the Culebra at
wells H-8b, DOE-I, and Engle, and in Cenozoic
alluvium at the Carper well.
4.6 Isolation Verification
Pressures above and below the tested interval are
monitored whenever possible during tests so that
any leakage around packers or other types of flow
into or out of the test interval fromfio above or below
can be detected. Slow, uniform pressure changes of
a few psi in the borehole intervals above and below
the test interval are not uncommon, as fluids from
these intervals may seep into the adjacent formations
or formation fluids may flow into relatively
underpressurized intervals. Abrupt, higher
magnitude pressure changes may indicate faulty
packer seats or equipment malfunctions.
Even when inflated to 2000 psi above ambient
borehole pressures, packers exhibit a degree of
compliance, or "give". Because some shut-in tools
require an up or down movement of the tubing string
with several tons of force, packers may shift very
slightly upward or downward. In an isolated interval
of the borehole, such as below the bottom packer,
the increase or decrease in volume caused by the
packer compliance is translated into a detectable
pressure change. Packer-compliance effects should
not be confused with pressure changes having other
causes. Differentiation is possible because packer
compliance typically causes abrupt pressure
changes at the time of tool movements or following
packer inflation, followed by a return to the predisturbance
pressure, whereas packer leaks or bad
seals between packers and the borehole or casing
wall usually result in continuous pressure changes or
equilibration between test-interval pressure and
annulus or bottomhole pressure.
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