Televiewers

Optical Teleview Head

Optical Teleview Head

Since the introduction of slimline borehole televiewers in the early 1990s, there has been a considerable increase in the use of televiewers across all industries, including mining exploration and production, geotechnical engineering, university research, and groundwater exploration.

With current tools delivering much higher resolution images and faster collection rates, both acoustic and optical televiewers have become mainstream in subsurface investigations.

Below you will find information on how acoustic and optical televiewers work, features of the second generation ABI and OBI tools, and the most common televiewer applications.

Acoustic televiewer overview

The QL40-ABI-2G is the latest generation of Acoustic Borehole Imager.  The tool generates an image of the borehole wall by transmitting ultrasonic pulses from a fixed transducer with rotating mirror and recording the amplitude and travel time of the signals reflected at the interface between borehole fluid and the formation (borehole wall).

The QL40-ABI-2G features multi-echo capability. This is achieved by digitally recording the reflected acoustic wave train. Real-time analysis of the acoustic data is made by the digital signal processor. Sophisticated algorithms allow the system to detect the reflection from the acoustic window and to separate and classify all subsequent echoes.

A built-in high precision orientation sensor incorporating a 3-axis fluxgate magnetometer and 3 accelerometers allows orientation of the images to a global reference and determination of the borehole’s azimuth and inclination.

Minimum input from the operator is needed to enable:

  • Automatic or manual adaptation to variable borehole conditions.
  • Improved dynamic range of signal detection.
  • Very high travel time resolution.
  • The implementation of different operating modes. For example, when run inside PVC casing, the tool can record both the echo of the PVC casing and that of the borehole wall. With multi-echoes processing, application of the tool may be extended to steel casing thickness and corrosion evaluation.
  • Tool upgrades can be done by simply downloading new firmware to the tool from the surface computer.

For more information and technical specifications, please go to the QL40-ABI-2G product page.

Optical televiewer overview

The QL40-OBI-2G is the new generation of slim hole Optical Borehole Imager. The system consists of a completely redesigned optical assembly and electronics, and uses a high-resolution CMOS digital image sensor combined with a fisheye lens.

The tool produces an extraordinarily sharp, continuous 360° unwrapped digital picture of the borehole wall, either in air or clear water. Resolution up to 1800 pixels over the borehole circumference can be achieved, making it ideal for lithological, mineralogical and structural analyses.

A built-in high precision orientation sensor incorporating a 3-axis fluxgate magnetometer and 3 accelerometers allows orientation of the images to a global reference and determination of the borehole’s azimuth and inclination.

For more information and technical specifications, please go to the QL40-OBI-2G product page.

Televiewer applications

  • Detailed and oriented structural information
  • Reference for core orientation
  • Fracture detection and evaluation
  • Breakout analysis
  • Detection of thin beds
  • Determination of bedding dip
  • Lithology and mineralogical characterization
  • Casing inspection
Acoustic Televiewer Image in WellCAD

Acoustic Televiewer Image in WellCAD

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