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Full-waveform Sonic

The RG full-waveform sonic provides multi-spacing digital acoustic-velocity (formation-slowness) measurements with high vertical resolution. Full-waveform recording and CBL measurements are also available.
The tool can be stacked with other tools in the RG oilfield range.

Principle of measurement:

A piezoelectric transmitter stimulated by a high-voltage pulse radiates a high frequency acoustic wave through the borehole fluid and formation to the receiver array. An accurate quartz clock measures the first-arrival transit time at each receiver.

Compensated sonic mode:

Two receivers and two transmitters are used. The probe measures the time of the first compressional arrival at each receiver from each transmitter firing. The data is depth-shifted and processed to remove the influence of the borehole fluid path, tool tilt and caving (depth-derived borehole compensation).

CBL mode:

The probe records the 3’ first arrival amplitude and 5’ full sonic wave train. The attenuation of the first arrival is related to the bond quality and the strength of cement.


  • High-energy transmitters for maximum penetration
  • Two monopole receivers and two monopole transmitters
  • Depth-deprived borehole compensation for borehole tilt and caving
  • Amplitude and waveform data in CBL mode with industry standard 3’ and 5’ spacing’s
  • Oil-filled mandrel with pressure compensation


  • Formation velocity (slowness)
  • Tx-Rx spacings: 3ft, 4ft, 5ft, 6ft
  • Compensated delta-t from each receiver pair
  • Cement Bond Log (CBL) amplitude and waveform


  • Open Hole
  • Lithology
  • Porosity
  • Rock strength and elasticity
  • Fracture indication
  • Time to depth correlation for seismic
  • Cased Hole
  • Location of poor or missing cement behind casing


  • Diameter: 63mm (2.5”)
  • Length: 4.45m (177”)
  • Weight: 51kg (112lb)
  • Max. temperature: 125°C
  • Max. pressure: 86MPa (12,500psi)
  • Range: 40 – 240µS/ft
  • (130 – 787µS/m)
  • Vertical resolution: 1ft or 2ft
  • Transmitter(s): 2 piezoelectric
  • Receivers: 2 piezoelectric
  • Frequency: 20kHz (nominal)

Operating Conditions

  • Sonic: 4” to 12” water-filled open hole
  • CBL: 4” to 12” water-filled cased hole
  • Centralisation: tool is normally run centralised

Sales Information

IO13889 Full-waveform sonic probe
I014803 6-arm centraliser (2 required)

Download Full-waveform Sonic sheet


...Practical Innovation with Global Service & Support...

Robertson Geologging Ltd., 2017

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(+44) 1492 582 323