High Resolution Acoustic Televiewer

The High Resolution Acoustic Televiewer (HRAT) provides a continuous high-resolution oriented ultrasound image of the borehole wall.

The probe uses a fixed acoustic transducer and a rotating acoustic mirror to scan the borehole walls with a focussed ultrasound beam. The amplitude and travel time of the reflected acoustic signal are recorded as separate image logs.

Features such as fractures reduce the reflected amplitude and appear as dark sinusoidal traces on the log. The travel-time log is equivalent to a 360-arm caliper and shows diameter changes within open fractures and ‘break-outs’. Directional information is also recorded and used to orient the images in real time.


Fracture identification and orientation

Stratigraphic studies

Local stress studies (break-out)

Core orientation

Cased-hole studies

Operating Conditions

Borehole Type    :Fluid filled

Recommended Logging Speed    :2.5m/min


Diameter        :42mm

Length            :1.99m

Weight            :5kg

Temperature (max)   :70°C

Transducer type        :1.5MHz piezo-composite

Rotation rate   :5 – 20rev/s

Sample rate     :up to 360/rev

Part Numbers

I002184    HRAT probe

I002192    HRAT including natural-gamma

Acquisition of HRAT data with Micrologger2