Electrical well logging

Contents Introduction

Borehole Environment

Types of Well logging

Types of Electrical Well logging

Resistivity Method

Self Potential method

Induction Logging

Conclusion

References

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.

Borehole Environment


Well Logging

1) Electrical Well logging

2) Radioactivity Well logging

3) Sonic Well logging

4) Miscellaneous 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.

Electrical Well logging

Electrical

Well Logging

1) Resistivity Method

2) Self Potential method

3) Induction 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.

Resistivity Method

Resistivity

Method

Normal and lateral Log

Microlog

Laterolog

Microlaterolog

Proximity log

Resistivity Method

Resistivity

Method


2) Laterolog

3) Microlog

4) Microlaterolog

5) Proximity log

The standard normal configuration The standard lateral configuration

Resistivity Method

Resistivity

Method


Microlog

Resistivity Method

Resistivity Method

Resistivity

Method


Microlog

Laterolog

The Laterolog configuration

N

M

C0

Working Principal of Laterolog

N

M

C0

C2'

C1'

C2

C1

Resistivity Method

Resistivity

Method


Laterolog

Microlog

Microlaterolog

Resistivity Method

Resistivity

Method


Laterolog

Microlog

Microlaterolog

Proximity log


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.


Electrical

Well Logging

Resistivity Method

Self Potential Method

Cl¯

Na⁺

Cl¯

Na⁺


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 resistivityTo estimate the fraction of clay.Correlation of permeable beds


Electrical

Well Logging

Resistivity Method

Self Potential method

Induction Logging

Fe, Mg richbody

ConclusionWell 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.

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

Electrical well logging

Education