Sage Acoustic Fluid Logger III, Reference Manual

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Acoustic Fluid Logger and Pressure Pulse Gas Gun
27
Shooting a Reverse Pressure Wave
The Pressure Pulse Gas Gun can be used to shoot both a positive pressure wave, using
compressed bottle gas, and a reverse pressure wave, using gas from inside the well being tested.
Important: A positive pressure wave will show the fluid level as the biggest kick down on the
trace. A reverse pressure wave will show the fluid level as the biggest kick
up.
The joints to the fluid level should be measured to the biggest downward kick on the positive
pressure tape, and to the biggest up-kick on the reverse pressure wave tape.
In the two examples, the same well was tested on different days, once using a positive pressure
wave, and once using a reverse pressure wave. The fluid level is visible as the largest kick on each tape,
as a mirror image between the positive and reverse shots. (Tapes were printed in 4-compressed mode.)
Reverse Pressure Wave Tape – fluid level kicks up on tape
Positive Pressure Wave Tape – fluid level kicks down on tape
Shooting a reverse pressure wave shot
The procedure for shooting a reverse pressure shot is much like shooting a positive shot, except
that gas escaping from the well is allowed to shoot into the gun chamber, instead of compressed gas
shooting into the wellbore and then into the gun chamber.
To shoot a reverse pressure shot: Push the gun into load position, look at the gauge on top of
the gun, and bleed down the pressure, with the relief valve, until the gauge reaches zero. Then close the
relief valve. The well now has higher pressure inside it than the gun does, setting up the reverse shot. Put
the fluid logger unit in standby mode, then fire the gun. Gas shoots from the wellbore into the gun, and
the fluid logger will record the reverse shot.