Sonic Test:

The Full Waveform Sonic probe uses a dual-transmitter dual-receiver array to provide high quality formation acoustic-velocity data.
Options are available for display of full-waveform data and cement-bond data (CBL) in cased boreholes.
Principle of Measurement:
A piezoelectric transmitter stimulated by a high-voltage pulse radiates a high-frequency acoustic wavelet. This is coupled via the borehole fluid and formation to each receiver. An accurate quartz clock measures the first arrival transit time. The first arrival in open hole corresponds to the p-wave path in the formation.
Full Waveform Sonic mode: Two pairs of transmitters and receivers are used to allow cancellation of the borehole fluid path and determination of formation velocity (slowness). The full sonic waveform from both receivers is displayed as a variable-density log (VDL) or waveform (‘wiggle’) trace.
Cement Bond Log (CBL) mode: The probe records the amplitude and arrival time of the first casing arrival at the near receiver and full sonic waveforms from both receivers.