4. WHAT IS CALIPER LOG:
Defined as a well log that shows the variations with depth in the
diameter of an uncased borehole.
It is produced by spring-activated arms that measure the varying
widths of the hole as the device is drawn upward.
5. The mechanical:
The measurements are made by two articulated arms pushed
against borehole wall, the arms are linked to the cursor of a
variable resistance.
Lateral movements:
The arm is translated into the movements of the cursor along the
resistance, the variations in output are translated into diameter
variations after
a simple calibration.
HOW IT IS WORK
11. Caliper log Use
1.Environmental corrections to other logs such as (GR, RHOB, NPHI) are
sensitive to hole size.
2.Contributory information for lithological assessment.
3.Indicator of good permeability and porosity zones (reservoir rock) due to
development of mud cake in association with gamma ray log.
4.Calculation of mud cake thickness, hmc = (dbit– dh)/2.
5.Selection of consolidated formations for wireline pressure tests, recovery of
fluid samples, well testing, and for determining casing setting depths.
6.Center or en-center logging-tool strings.
7.Estimate the volumes of gravel and cement for well-completion planning.
