Operation of the Model M with the Compact Gas Gun
The compact gas gun is to be operated in the COMPRESSION (Explosion) or RAREFACTION (Implosion) mode. The
operator should use the Compression (explosion) technique when the casing pressure is less than approximately 100 psig.
The Rarefaction (implosion) technique may be used whenever the casing pressure is sufficient to obtain a good record.
COMPRESSION (EXPLOSION) MODE
Expansion of gas from the Echometer gas gun is used to generate a pressure pulse. The pressure pulse is positive since the
gas chamber is charged to a pressure that exceeds the well pressure by at least 100-psi.
1.
Securely attach the Echometer Gas Gun to the
Casing Valve
.
2.
Close the
Casing Pressure Bleed Valve
and
Filler Bleed Chamber Valve
.
3.
Lift the
Cocking Arm
to close the internal gas valve. This prevents debris from entering the volume chamber.
4.
Open the
Casing Valve
to the Echometer Gas Gun slowly and
Close
the casing valve to the flow line.
5.
Measure the Casing Pressure using the precision pressure gauge.
6.
Record
Time
and
Casing pressure.
7.
Fill the volume chamber with gas (CO2 or N2) to at least
100-psi in excess
of the
Casing Pressure
.
8.
Connect the coaxial cable from the microphone to the
Input
of the Model M.
9.
Turn
Power Switch
to
ON.
10.
Select the type of collar response desired and set the gain controls to
AUTO.
11.
Turn
chart drive ON.
12.
Generate pressure pulse by pulling
Trigger
Ring
, after “
Generate Pulse
” is displayed on chart.
13.
Turn chart drive
OFF
after detecting the liquid level signal.
14.
Inspect the record and repeat the shot if the signal quality is not satisfactory.
15.
Turn power switch to
OFF
after operation.
16.
Record
Time
and
Casing Pressure
.
17.
Close
the Casing Valve between Echometer Gas Gun and the well
.
18.
Open the
Casing Pressure Bleed Valve
and release the pressure.
19.
Open the Casing Valve to the flow line.
20.
Remove the Echometer Gas Gun from the casing valve.
RAREFACTION (IMPLOSION) MODE
Gas is released from the well into the gas gun volume chamber to generate the initial pulse. Debris, moisture, corrosive
liquids and chemicals, and other foreign material may be imploded into the gas gun volume chamber, which will increase
maintenance requirements and may cause corrosion on the inside of the volume chamber.
1.
Securely
attach
the Echometer Gas Gun to the
Casing Valve
.
2.
Close the
Casing Pressure Bleed Valve
and
Filler Bleed Chamber Valve
.
3.
Open the
Casing Valve
to the Echometer Gas Gun slowly and
Close
the casing valve to the flow line.
4.
Pull
Trigger Ring.
5.
Lift the
Cocking Arm
to close the internal gas valve.
6.
Measure the Casing Pressure using the precision pressure gauge.
7.
Record
Time
and
Casing Pressure.
8.
Bleed
the gas chamber pressure through the Filler-Bleeder Chamber Valve by rotating the knob clockwise until the
gas gun pressure has decreased to approximately 200-psi below the casing pressure reading. Use greater or less
differential pressure depending on the quality of the recording.
9.
Connect the coaxial cable from the microphone to the INPUT of the Model M.
10.
Turn
Power Switch
to
ON.
11.
Select the type of collar response desired and set the gain controls to
AUTO.
12. Turn
chart drive ON.
13. Generate pressure pulse by pulling
Trigger
Ring,
after “
Generate Pulse
” is displayed on chart.
14.
Turn chart drive
OFF
after detecting the liquid level signal.
15.
Inspect the record and repeat the shot if the signal quality is not satisfactory.
