UK T. (+44) 1492 582 323

Americas T. +1 (559) 456-1711

Asia T. (+852) 6503 3486

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.


  • Down-hole digitisation of waveform data
  • Compensation for poor centralisation or caving
  • Variable density log (VDL) or wavelet (wiggle) display


  • Formation velocity (slowness)
  • Shear (S) velocity (where shear wave exists)
  • Full waveform Time of first arrival (delta-t)
  • Amplitude of first arrival (CBL)
  • Integrated transit time


  • Water/minerals/engineering
  • Porosity
  • Rock strength and elasticity (with other logs)
  • Correction of seismic velocity
  • Fracture and permeability indication in hard rock
  • Location of poor or missing cement behind casing


Diameter: 60mm
Weight: 24kg
Temperature: 0-70⁰C (extended ranges available)
Max. pressure: 20MPa

Operating Conditions

Borehole type:

  • Sonic: open-hole, water-filled CBL: cased-hole, water-filled
  • Centralisation: required

Sales Information

I002128 Full-waveform sonic probe with CBL


Download Full-waveform Sonic Probe sheet


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

Robertson Geologging Ltd., 2017

how can we help you?

(+44) 1492 582 323