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Well logging course for fourth year
Geophysics
By
Dr. Adel Kamel Mohamed
The syllabus of Well Logging course
Course Title: principles and application of well logs
Objectives: At the end of this course, the students should be able to understand the basics of
borehole geophysics, theory of measurements, interpretations and applications of the
different types of wire line logs.
Students should also know how to calculate the
petrophysical parameters required for formation evaluation (source and reservoir rocks).
Course construction:
Strategy: 12 lectures.
General divisions
Chapter 1 Introduction
Chapter 2 Borehole Environment & Recording Formats of logs
Chapter 3 Electrical Logs
Chapter 4 Radioactive Logs
Chapter 5 Acoustic Logs
Chapter 6 Thermal Logs
Chapter 7 Imaging logs
Chapter 8 Quick Look Interpretation of Wire line Logs
Chapter 9 Application of well logging in different fields (formation
evaluation).
References:
Asquith, G. and Krygwski, D. (2004): Basic well log analysis” The American Association of
Petroleum Geologists, Tulsa, Oklahoma.
Rider, M.H. (1996):”The geological interpretation of well logs” 2nd edition, Blackie and Son
Limited, London, UK.
Schlumberger (1987): “Principles and application of well logs“ Schlumberger Ltd., France.
Web Site: www.brookes.ac.uk/geology/peg/short course
www.chee.uh.edu/petroleum/PETR6304
Items of lecture
Historical overview on the well logging technique.
- What is a “Log”
- Types of boreholes and well logs.
- Well logs; the necessity.
- Logging companies.
- Objectives of wire line logs.
- Principal uses of wire line logs.
Figure shown represents the first well logging
record by Henri Doll in 1927
Schlumberger Logging
Trucks in the past
Types of boreholes
 According to Casing operation
- Cased holes
- Open holes
 According to conductivity of the borehole
- Conductive (water base drilling mud)
- Non-conductive boreholes (oil base mud, air
drilled or cased holes)
Cased holes
Open holes
Types of well logs
Wireline logs
(Electrical, Radioactive, Acoustic,
mechanical, Thermal and Magnetic logs)
Formation Testers
(Repeated Formation Tester, Drill Stem
Tests)
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Well logs- the necessity
These measurements are necessary because
geological sampling during drilling (cutting
sampling) leaves a very imprecise record of the
formations encountered.
Entire formation samples can be brought to the
surface by mechanical coring, but this is both
slow and expensive.
The results of coring, of course, are unequivocal.
Logging is precise, but equivocal, in that it needs
interpretation to bring a log to the level of
geological or petrophysical experience.
However, logs fill the gap between ‘cuttings’ and
cores, with experience, calibration and
computers, they can almost replace cores, as they
certainly contain enough information.
Some Logging Companies
 Schlumberger
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Gearhart
Dresser Atlas
Welex
Haliburton
Others
Objectives of wire line logging
1-Lithology identification
2-Determination of reservoir characteristics (e.g. porosity,
saturation, permeability).
3-Discrimination between source and non source rocks
4-Identification the fluid type in the pore space of
reservoir rock ( gas, oil, water)
5-Identification of productive zones.
6-Determination the depth and thickness of productive
zones.
7-Locating reservoir fluid contacts.
8-Well to well correlation for determining the lateral
extension of subsurface geologic cross sections.
9-Determination formation dip and hole angle and size.
Principal uses of open hole wireline logs