Downhole
Shut-in Tool
A
typical deployment of the "downhole" shut-in tool
is below a lock mandrel and equalising sleeve with a shock absorber
situated between the shut in tool and the memory gauges below.
The
Shut in Tool is set to operate at surface with a time delay,
which can be programmed into the tool either via a Personal
Computer or, more typically, through Nan Gall Energy Systems's hand
held programming device.
Quartz
memory gauges, when used in conjunction with a "downhole"
Shut-in Tool can produce many benefits when compared with "shut-ins"
at surface.
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Disadvantages
of "surface shut-in" include;
- wellbore
storage effects during pressure build up surveys masking
the reservoir flow period and rendering interpretation
extremely difficult
- leaking
flow-line valves on many older wells resulting in
true surface "shut in" not being achieved
- large
gas caps forming in oil-gas wells giving erroneously
high bottom hole pressures
- the
length of time wells must be shut-in to achieve useful
bottom hole pressure information
- pressure
fall-off data following water injection being distorted
by the hydrostatic column above the gauges
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Deployment of the simple to operate Nan Gall Energy Systems shut-in
tool can remove the disadvantages above and provide improved
bottom-hole condition information.
