Warning
Sasquatch only works with plungers that have ferrous content. Sasquatch must see the Earth’s magnetic field disrupted by the plunger.
Overview
Sasquatch works by watching a ferrous plunger go by in real time, correlating multiple key points on two separate waveforms.
Detection Issues
If the plunger is not ferrous, no waveforms are seen leading to a zero velocity being reported. While an arrival may be detected from moving parts at the well head, if the waveforms are not detectable and correlated.
Confidence Codes/Measurement Status
Along with each arrival velocity, a confidence code or measurement status is reported. This can be used to determine whether the value being reported is valid.
Based on Firmware Version 1.2.0 or later, values are:
- -32768: Not Initialized
- -1: Velocity Under Range
- -2: Velocity Over Range
- -3, -4: Velocity Calc Error
- 2 to 8: These represent the number of points successfully correlated
- All other numbers are invalid
Confidence codes in earlier versions of firmware were:
- 0: Not Initialized
- 1: Velocity Calc Error
- 2 to 8: These represent the number of points successfully correlated
- 20: Velocity Under Range
- 21: Velocity Over Range
- 22: Velocity Calc Error
- All other numbers are invalid