ADDITIONAL NOTES
The specified accuracy is achieved provided certain conditions are met. Since the
distance calculation is determined by timing the returned echo, it is important that a
free path is available for the pulse to travel to the water surface and return. It is
possible that an obstruction such as torque arrester or centering ring on a pump pipe
can cause a premature echo or distort the pulse causing the effective pulse to shift one
way or the other. It is also possible that a breakout or large fracture opening can also
cause a false echo. Ordinary pump piping and wiring will not interfere with the
measurements.
The accuracy is also dependent on the sound speed in the well. Since the sound
speed is determined by the temperature, the average temperature must be specified
correctly. The error is approximately .1%/°F.
The maximum range is limited by the maximum time during which the echo is
monitored, and the strength of the echo signal. Uncased wells drilled through porous
material can attenuate the signal faster than the rated distance, making detection
impossible.
Eno Scientific Well Watch 670
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