Sonic - Slimhole

45mm Full-waveform Triple Sonic Probe

This highly compact slimhole tool is designed specifically for geotechnical and mining applications. The probe acquires transit-time and full-waveform data simultaneously from a single transmitter and three receivers.

Principle of Measurement: The piezoelectric transmitter is stimulated by a high-voltage pulse and radiates a high-frequency acoustic wave through the borehole fluid and formation to each receiver. An accurate quartz clock measures the first arrival transit time.

Compensated sonic mode: Three receivers are used. The probe measures the time of the first compressional arrival at each receiver. The difference in arrival times between each pair of receivers allows determination of formation velocity independent of the borehole fluid path.

Full-wave sonic mode: The probe records the full sonic wave-train at all receivers simultaneously. This can be displayed either as a variable-density log (VDL) or as a waveform (wiggle trace). The waveform data may be exported to packages such as WellCAD™ for calculation of compressional, shear and Stoneley velocities.


  • Short probe can be handled by single operator and easily transported
  • Slim diameter for narrow boreholes
  • Rigid construction for effective centralisation
  • Down-hole digitization of waveform data
  • Detection gain and threshold under operator control.
  • Detection point and wavelet display shown in real time.


  • Formation velocity (slowness)
  • Time of first arrival (delta-t)
  • Integrated transit time
  • Full-waveform data from 3 receivers
  • Shear and Stoneley velocities (requires additional interpretation software)
  • Natural gamma


  • Geotechnical/mining/water
  • Fracture and permeability indication in hard rock
  • Rock strength and elasticity
  • Lithology identification
  • Porosity
  • Correction of seismic velocity

Operating Conditions

  • Borehole type:
  • Sonic: open-hole, water-filled
  • Centralisation: 2 essential


  • Diameter: 45mm
  • Weight: 8kg
  • Temperature: 0-70⁰C (extended ranges available)
  • Max. pressure: 20MPa

45mm Full-waveform Triple Sonic Probe

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