Electrical well logging

2. Contents
Introduction
Borehole Environment
Types of Well logging
Types of Electrical Well logging
Resistivity Method
Self Potential method
Induction Logging
Conclusion
References

3. Introduction
• Well Logging involves measuring the physical
properties of surrounding rocks with a sensor located
in a borehole. The record of measuring as a function
of depth is called as well logging.

4. Borehole Environment

5. Types of Well logging
Well Logging
1) Electrical Well logging
2) Radioactivity Well logging
3) Sonic Well logging
4) Miscellaneous well logging

6. Types of Well logging
Well Logging
1) Electrical Well logging
 We used to measure lithological variations in
borehole by measuring their electrical
properties.
It has been observed that in a borehole, the
electrical potential varies according to the
nature of the beds traversed.

7. Electrical Well logging
Electrical
Well Logging
1) Resistivity Method
2) Self Potential method
3) Induction Logging

8. Electrical Well logging
Electrical
Well Logging
1) Resistivity Method
It works by characterizing the rock or sediment in a
borehole by measuring its electrical resistivity.
In the Sedimentary rocks most of the minerals are
non-conductors (Silicates and Carbonates), but
presence of water in the pore spaces can conduct
electricity.
In Metamorphic and Igneous rocks certain
minerals can contribute their conductivity.

9. Resistivity Method
Resistivity
Method
 Normal and lateral Log
 Microlog
 Laterolog
 Microlaterolog
 Proximity log

10. Resistivity Method
Resistivity
Method
 Normal and lateral Log
2) Laterolog
3) Microlog
4) Microlaterolog
5) Proximity log
The standard normal configuration The standard lateral configuration

12. Resistivity Method
Resistivity
Method
 Normal and lateral Log
 Microlog

13. Resistivity Method

14. Resistivity Method
Resistivity
Method
 Normal and lateral Log
 Microlog
 Laterolog
The Laterolog configuration

15. N
M
C0
Working Principal of Laterolog

16. N
M
C0
C2'
C1'
C2
C1

17. Resistivity Method
Resistivity
Method
 Normal and lateral Log
 Laterolog
 Microlog
 Microlaterolog

18. Resistivity Method
Resistivity
Method
 Normal and lateral Log
 Laterolog
 Microlog
 Microlaterolog
 Proximity log

19. Electrical Well logging
Electrical
Well Logging
 Resistivity Method
The determination of resistivity for
formations is essential to determination of
saturation mainly of the hydrocarbon.
True formation resistivity and flushed zone
resistivity.
Mud filtrate Invasion profile.

20. Electrical Well logging
Electrical
Well Logging
 Resistivity Method
 Self Potential Method

21. Cl¯
Na⁺

22. Cl¯
Na⁺

23. Electrical Well logging
Electrical
Well Logging
 Resistivity Method
 Self Potential Method
To delineate porous and permeable reservoir
rocks
To determine bed boundaries and bed
thickness
To evaluate the formation water resistivity
To estimate the fraction of clay.
Correlation of permeable beds

24. Electrical Well logging
Electrical
Well Logging
 Resistivity Method
 Self Potential method
 Induction Logging

27. Fe, Mg rich
body

28. Conclusion
 Well logging is the detailed survey, conducted after the location
for drilling is fixed based on the other preliminary geological
and geophysical surveys.
 In the normal resistivity logging method, if the thickness of the
bed is less than the separation between AM, then we will get
reverse graph.
 In the resistivity well logging method we use our own source
but in the case of SP method we use natural current.
 Proximity well logging is use to determine the density of the
reserves.

29. Books:-
 Philip Kearey, Michael Brooks, Ian Hill (2002), An Introduction to
Geophysical Exploration, Third Edition, Blackwell Science Ltd, Pp 236-244
 W.M. Telford, L.P. Geldart, R.E. Shrriff (1990), Applied Geophysics,
Second Edition, Cambridge University Press, Pp 645-658
 Darwin V. Ellis & Julian M. Singer (2007), Well Logging for Earth
Scientists, Second Edition, Springer. Pp 41-59
Websites:-
 http://www.greatgeophysics.com/logginginfo.html
 http://en.wikipedia.org/wiki/Well_logging
 http://petrofed.winwinhosting.net/upload/IAI/17-
20mar10/WellLoggingTech.pdf
 http://petrowiki.org/Electrode_resistivity_devices