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3AC38: Three-arm caliper probe

By means of three spring-loaded arms maintained in contact
with the borehole wall, the
3AC38 probe provides a
representative measurement of the borehole diameter.

The standard probe nose section and arms provide a high-resolution measurement over the diameter range from 40 to 300 mm. If the supplied arm extensions and nose section extension tube are installed, the upper diameter limit is increased to 700 mm.

As an indicator of enlarged zones or fractures, this log is useful
both in assessing the competence of the formations and as a
basis for calculating environmental corrections for other
logging parameters such as fluid flow and production
assessment. The basic open-hole diameter log can be
integrated over depth to calculate an accurate borehole
volume for cementing or gravel-packing operations.


The probe is also useful for quality control purposes, for
example to verify the depth and diameter of casings and
screens installed in a water well.
As an option, the probe can be supplied with a natural gamma
detector to provide additional lithological information or for horizon corelation purposes.

Contact us to get a quote or request more information.

3AC probe diagram



Technical Specifications

✓ Diameter : 38 mm

Length : 2360 mm (short arms)

                 2470 mm (long arms)

Weight : 8 kg

 Max. Temperature : 70°C

Max. Pressure: 200 bar

Power supply: 70 to100 Vdc


Data / Sensor parameters

Diameter range: 40 to 700 mm

 Diameter resolution: 0.1 mm



Options and Accessories

 Natural Gamma detector :

ø25x50 mm NaI(Tl) crystal

 calibration jig 


Borehole Conditions

Open or cased borehole

  Fluid filled or dry borehole 

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