Page 154 - The Geological Interpretation of Well Logs

- THE GEOLOGICAL INTERPRETATION OF WELL LOGS -

coal SEDIMENTARY
||LOG
organic shale
shale _
silt
fi. sd. {
GAMMA-RAY API

me, sd. || || NEUTRON POROSITY UNITS % THIN SECTION
CONSTITUENTS
0%
50% 1
1

matter
quartz porosity clay
yeance organic
Sea up

coarsening
.

Figure 10.19 Changes in the neutron log correlatable with changes in quartz admixture, The higher the quartz content, the lower
the neutron value.

SEDIMENTARY re
LOG (core)
organic mat. |
thin section
%

NH NEUTRON POROSITY UNITS % 0
ri keg «=«|60 45 30 15 Y
at | i { 40° 20 | 9 5

rm : "
_-_ +
= «— organic matter peak
™_™ ~~ — —_.
> 7
—_— qn
—
i E
— 5
> q
u 10 3 m
<=
= y
x
= organic matier peak
a ye pe
a 7
o>
Ou
a: 3 |
>
=
Fr) 20m

a H
<= 7g organic matter peak
=<
—>
Ra
5 a

Figure 10,20 The effect of organic matter on the neutron Jog. Organic matter has a high hydrogen index and causes a moderate
increase in the neutron jog values.
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