Full-waveform Sonic Probe
The RG 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.
Compensated sonic mode: two pairs of transmitters and receivers are used to allow cancellation of the borehole fluid path and determination of formation velocity.
Full-waveform sonic mode: A single transmitter and two receivers are used. The probe records the full sonic waveform at both receivers simultaneously and also the velocity of the first arrival.
Cement-bond log (CBL) mode: A single transmitter and two receivers are used. The probe records the amplitude and arrival time of the first casing arrival at the near receiver and full sonic waveforms at both receivers.