This document discusses formation density logs. It describes the components of a density tool, including a radioactive source and two detectors. It explains that density tools bombard the formation with radiation and measure the amount that returns to a sensor. The document also discusses how density logs can be used to determine total porosity, recognize gas-bearing zones, identify minerals, and help identify lithologies when combined with neutron logs.

1. Name: Parimal Mahato
Applied Geology M.Sc ( 3rd sem)
Durgapur Govt. College

2. Gamma log has three types-
1.True gamma log /Normal gamma log
2.Spectral gamma log
3.Gamma-Gamma log /Scattered gamma log

3. PRINCIPLE
 The formation density tools are induced
radition tools
 They bombard the formation with radition
and measure how much radition returns to a
sensor

4. DENSITY TOOL

5. Tool consist of-
 A radioactive source: Caesium-137 and Cobalt-60
 A short range detector: Placed 7 inches from the
source.
 A long range detector: Placed 16 inches from the
sources.
PROCESS OF MEASURING

6. DETERMINATION OF POROSITY
 The porosity of a
formation can be obtain
from the bulk density if
the mean density of the
rock matrix and that of
the fluids it contains are
known.
fma
bma







7. LOG PRESENTATION

8. The effect of gas on the formation

9. USES OF THE FORMATION DENSITY
LOG
 Determine total porosity of the formation.
 Recognition of gas bearing zone.
 Identification of minerals(particularly
evaporites).
 The combination of formation density log
data with neutron log data gives one of the
best ways of identifying lithologies in a
borehole.

10. References
 Ellis, D. V., & Singer, J. M. (2007). Well logging for earth
scientists(Vol. 692). Dordrecht: Springer.
 Darling, T. (2005). Well logging and formation evaluation.
Elsevier.
 Johnson, D. E., & Pile, K. E. (2002). Well logging in
nontechnical language. PennWell Books.

11. THANK YOU