This document provides an overview of conventional wireline logging and formation evaluation. It begins with an introduction to well logging, formation evaluation, and petrophysics. It then outlines an agenda covering various logging tools including temperature, caliper, self-potential, resistivity, gamma ray, sonic, density, and neutron logs. For each tool, it provides details on the measurement principle, log presentation, and applications for formation analysis. The overall document serves as an introduction for understanding well logging methods and their use in characterizing subsurface formations.
2. Conventional wireline Logging and Formation Evaluation
By
Abd Al Rahman Ibrahim Soliman,
BSc of Geoscience,
Faculty of science, Alexandria University.
abdalrahmanibrahim209@gmail.com
3. 3
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10. Photoelectric Factor (PEF)
4. 4
What We Need for a Success
Well Logging and Formation Evaluation
A Rube Goldberg View
of a Hydrocarbon System
A “Kitchen”
Where Organic
Material Is
Cooked
A “Container”
From Which
Oil & Gas
Can Be
Produced
“Plumbing” To Connect
the Container to the Kitchen
Correctly
Placed
Wells
5. 5
Introduction
Well Logging and Formation Evaluation
0
2
4
6
8
Oil & Gas
Generation
Window
Gas
Generation
Window
Depth(km)
Source
Reservoir
Trap & Seal
Migration
Gas & Oil
No More
HC Generation
79. 79
Introduction
Well Logging and Formation Evaluation
Wireline Logging…Continuous recording of geophysical parameters along a borehole (With depth), to produce
geophysical well log.
Petrophysics…Is the study of rock properties and their interactions with fluids(oil, gas, and water). Study occur
on Core samples.
Formation Evaluation…is the process of using borehole measurements to evaluate the characteristics of
subsurface formation.
85. 85
Solving The Jigsaw
Well Logging and Formation Evaluation
85
PETROPHYSICS
GEOLOGY
DRILLING RESERVOIR ENGINEERING
GEOPHYSICS
- Facies characterization
- Structural
- Sand bodies distribution
- Seismic facies
- Rock Physics
- Synthetic seismic/Tie-in
- Fluids /contatcs
- Pressure/Compartments
- Relative permeability
- Rock mechanics
- Data Acquisition
- Real time drilling optimization
Where
what to
drill
Targetting
hydrocarbons
, P&T
compartm
ents
Model
update
(4D)
Model
Maps
Volumes
98. 98
Introduction
Well Logging and Formation Evaluation
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.
99. 99
Introduction
Well Logging and Formation Evaluation
Well A Well DWell CWell B
Coastal Plain Sandstones and Mudstones
Shallow Marine Sandstones
Shelf Mudstones
100. 100
Introduction
Well Logging and Formation Evaluation
Here the correlation is based on common
lithologic units
Well A Well DWell CWell B
Datum
Coastal Plain
Nearshore Sands
Shelf Mudstones
101. 101
Introduction
Well Logging and Formation Evaluation
Here the correlation is based on an
interpretation of time-equivalent stratal
packages – i.e., parasequences
Well A Well DWell CWell B
Coastal Plain
Shelf Mudstones
Index
Fossil
104. 105
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10. Photoelectric Factor (PEF)
105. 106
Introduction
Well Logging and Formation Evaluation
• The Temperature Log is a tool for measuring the borehole
temperature.
• Temperature sensors are attached to every tool
combination that is run in a well for the measurement of
the maximum temperature (assumed to be at the bottom
of the well),
• and a few modern tools exist that can continuously
measure temperature as the tool travels down the well.
106. 107
Introduction
Well Logging and Formation Evaluation
• Readings from a number of the maximum thermometers
attached to different tool combinations and run at
different times are analyzed to give the corrected
temperature at the bottom of the borehole (bottom hole
temperature, BHT).
108. 109
Geothermal gradient Vs Thermal conductivity
Well Logging and Formation Evaluation
Geothermal Gradient…Rate of increasing temperature
and pressure with depth.
Thermal Conductivity…The efficiency of the formation to
transmits heat.
𝑮 =
𝑻𝒇 − 𝑻𝒔
𝑫𝒆𝒑𝒕𝒉
Where G….Geothermal Gradient, Tf…Formation
Temperature, Ts…Average surface temperature.
119. Break out
Well Logging and Formation Evaluation
result of inter action of stresses induced by drilling and
the existing stress regime of the country rock.
120. Uses of the Caliper Log
Well Logging and Formation Evaluation
Indicator of:
1. good permeability and
porosity zones.
2. mud cake thickness.
3. borehole volume.
4. cement volume.
5. hole quality .
121. 122
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
130. 131
Static SP and shale base line .
Well Logging and Formation Evaluation
131. 132
SP anomalies
Well Logging and Formation Evaluation
• saw toothed profile .
1. related to invasion condition .
2. Related to Noise .
132. 133
Factors affecting SP .
Well Logging and Formation Evaluation
1-Oil-base muds.
2-Hydrocarbon saturation suppresses SP
deflections.
3- Unbalanced mud columns.
4- Bed thickness .
5- Resistivities.
133. 134
Application of SP log.
Well Logging and Formation Evaluation
1-Detection of permeable
beds.
2- Location of bed
boundaries.
3- Delineation of shale
beds.
134. 135
Application of SP log .
Well Logging and Formation Evaluation
4- Determination of Rw (formation water resistivity).
5- Determination of shale
volumes .
135. 136
Application of SP log .
Well Logging and Formation Evaluation
6- Indications on the environment of deposition.
136. 137
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
137. Introduction
Well Logging and Formation Evaluation
Resistance… is the obstruction offered to the flow of current by a
conductor.
Resistivity… is the obstruction offered to the flow of current by
UNIT AREA OF the conductor.
Conductivity…is the ability of current to flow through material
So basically, resistance is the property of the object (say a copper
wire), whereas resistivity is the property of the substance
(copper).
And so resistance depends upon the properties of the object.
Whereas resistivity depends upon the properties of the metal.
140. Introduction
Well Logging and Formation Evaluation
Most rock materials are essentially insulators while their encl
osed fluids are conductors.
Hydrocarbons are the exception to fluid conductivity and on
the contrary they are infinitely resistive.
143. Golden Rule
Well Logging and Formation Evaluation
Most rock materials are essentially insulators. While
their enclosed fluids are conductors. Hydrocarbons are
the exception to fluid conductivity, and on the contrary ,
they are infinitely resistive. When a formation is porous
and contains salty water the overall resistivity will be
low .When this same formation contains hydrocarbons,
its resistivity will be very high.
145. Formation Resistivity factor
Well Logging and Formation Evaluation
The conductivity of the rock in general should be that of
the solution it contains. But it is not. Although the rock
plays no active part. It plays an important passive one
.This passive role is basically dependent on rock
texture or more specifically on the geometry of the
pores and pore connections
148. -Factors affecting measurement
Well Logging and Formation Evaluation
1.Hole diameter d
2.Mud resistivity Rm
3.Bed thickness
4.Resistivity of surrounding bed Rs
5.Resistivity of invaded zone Ri
6.True resistivity of zone Rt
7.Diameter of invaded zone di
152. Induction log Vs conventional resistivity log
Well Logging and Formation Evaluation
153. Log presentation
Well Logging and Formation Evaluation
R (Resistivity)= 1000/C (Conductivity)
curve is printed on the far right hand scale, track 4. The
conductivity measurements are automatically reciprocated
and a plot of the processed equivalent resistivity is found on
track 3
154. Uses of Resistivity log
Well Logging and Formation Evaluation
The Archie Equation and Water saturation calculation
𝑆𝑤 =
𝑛 𝑅𝑜
𝑅𝑡
or 𝑆𝑤 =
𝑛 𝐹×𝑅𝑤
𝑅𝑡
𝑭 =
𝑅𝑜
𝑅𝑤
.......... 𝐹 =
𝑎
∅ 𝑚 …………………..𝐼 =
𝑅𝑡
𝑅𝑜
155. Uses of Resistivity log
Well Logging and Formation Evaluation
Symbol Illustration
F Formation resistivity factor
Ro the resistivity of a rock with I 00% water
Rw Formation water resistivity
Rt True resistivity
Rxo Resistivity of flushed zone
Rmf Resistivity of mud filtrate
Sw Water saturation
Sxo flushed zone water saturation = 1.0 – RHS (residual hydrocarbon saturation)
a Tortuosity factor
m Cementation factor
n Saturation component usually 2
I The resistivity index
∅ Porosity
156. 157
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
166. 167
Uses……..Shale volume
Well Logging and Formation Evaluation
𝑰𝑮𝑹 =
𝑮𝑹 𝐥𝐨𝐠 − 𝑮𝑹 𝒎𝒊𝒏
𝑮𝑹 𝐦𝐚𝐱 − 𝑮𝑹 𝒎𝒊𝒏
Gas bearing zone
Oil bearing zone
Water bearing zone
167. 168
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
168. 169
sonic logs
Well Logging and Formation Evaluation
• The first arrival or compressional wave .
o The shear wave .
o The mud wave .
o The Stoneley wave .
169. Principle of measurment
Well Logging and Formation Evaluation
• log that measures interval transit time (Δt) of a
compressional sound wave travelling through the
formation along the axis of the borehole
∆𝑡 =
106
𝑣
the BHC: borehole compensated sonic tool
the LSS: long-spaced sonic tool
173. 17
4
Uses of the Sonic Log
Well Logging and Formation Evaluation
1.Porosity Determination
a. The Wyllie Time Average Equation
The velocity of elastic waves through a given lithology
is a function of porosity. Wyllie proposed a simple
mixing equation to describe this behavior and called it
the time average equation.
174. 17
5
Uses of the Sonic Log
Well Logging and Formation Evaluation
1.Porosity Determination
b. Secondary and Fracture Porosity
The sonic log is sensitive only to the primary
intergranular porosity. By contrast, the density and
neutron logs record the total porosity. The difference
between the two measurements, therefore, can be
used to calculate a value for the secondary porosity
(SPI or ϕ2)
175. 17
6
Uses of the Sonic Log
Well Logging and Formation Evaluation
1.Porosity Determination
c. The Raymer-Hunt Equation
176. 17
7
Uses of the Sonic Log
Well Logging and Formation Evaluation
177. 178
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
178. 17
9
DENSITY LOG
Well Logging and Formation Evaluation
Density log measures the bulk density of the formation.
Its main use is to derive a value for the total porosity of
the formation. It's also useful in the detection of gas-
bearing formations.
179. 18
0
Theory
Well Logging and Formation Evaluation
• Dense formations absorb many gamma rays, while low-
density formations absorb fewer. Thus, high-count rates
at the detectors indicate low-density formations,
whereas low count rates at the detectors indicate high-
density formations.
• For example, in a thick anhydrite bed the detector count
rates are very low, while in a highly washed-out zone of
the hole, simulating an extremely low-density formation,
the count rate at the detectors is extremely high.
183. 18
4
Uses of the Formation Density Log
Well Logging and Formation Evaluation
1. The main use of the formation density log is to determine
quantitatively porosity.
2. the recognition of gas-bearing zones, and the
identification of minerals (particularly evaporites).
3. The combination of formation density log data with
neutron log data gives one of the best ways of identifying
lithologies in a borehole.
184. 18
5
Uses of the Formation Density Log
Well Logging and Formation Evaluation
Porosity calculation:
Grain (matrix) densities of some common rock
forming minerals.
185. 186
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
186. 18
7
Neutron log
Well Logging and Formation Evaluation
In clean reservoirs containing little or no shale, the neutron
log response will provide a good measure of formation
porosity if liquid-filled pore spaces contain hydrogen, as is
the case when pores are filled with oil or water (hydrogen
index =1).
The neutron log is sensitive mainly to the amount of
hydrogen atoms in a formation. Its main use is in the
determination of the porosity of a formation.
189. 19
0
Uses of the Neutron Log
Well Logging and Formation Evaluation
Gas Effect
190. 19
1
Porosity Logs
Well Logging and Formation Evaluation
2. Determination of Lithology using the Neutron-Density Combination
give a direct measurement of TOTAL porosity.
Clean Formations
• There is no separation for pure limestones, and the
porosity value that the log gives is accurate.
• There is a small negative separation for clean sandstones.
• There is a moderate positive separation for pure
dolomites.
192. 193
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
193. 19
4
THE LITHO-DENSITY LOG
Well Logging and Formation Evaluation
The litho-density log is a new form of the formation density
log with added features. It is typified by Schlumberger’s
Litho-Density Tool (LDT). These tools have a caesium-137
source emitting gamma rays at 0.662 MeV, a short-spaced
and a long-spaced detector in the same way as the basic
formation density tool. However, the detectors are more
efficient, and have the ability to recognize and to count
separately gamma rays which have high energies (hard
gamma rays: 0.25 to 0.662 MeV) and gamma rays which
have low energies (soft gamma rays: 0.04 to 0.0 MeV).
196. 19
7
Log Presentation
Well Logging and Formation Evaluation
photo-electric factor log
(PEF). It is shown in tracks
3 together with the
formation density and
neutron curves. Scales
running from 0 to 10 or 0
to 15 or 0 to 20
barns/electron
198. 199
Agenda
Well Logging and Formation Evaluation
1.Introduction
2.Temperature log
3.Caliper log
4.Self potential Log, and Induction Log
5.Resistivity Log
6.Gamma Ray log
7.Sonic (Acoustic) Log
8.Density Log
9.Neutron Log
10.Photoelectric Factor (PEF)
199. 200
References
Well Logging and Formation Evaluation
Formation Evaluation and Petrophysics [Mr D. G. Bowen].
Basic Well Log Interpretation 2012. SHAHNAWAZ MUSTAFA.
Basic Well Log Analysis (2nd ed.) [G. Asquith, D. Krygowski, 2004].
The geological interpretation of well logs / Malcolm Rider. - 2nd ed.
Principles of Mathematical Petrophysics [Edward D. Holstein, Larry W. Lake, 2014].
Well_Logging_in_Nontechnical_Language__2nd_ed.Johnson Pile, 2006.
Schlumberger Log Interpretation Principles-Applications (1989).
Practical Petrophysics [M. Kennedy, 2015].
Well Logging for Earth Scientists By Darwin & Julian
Principles of Mathematical Petrophysics [Edward D. Holstein, Larry W. Lake, 2014]
Schlumberger, Log Interpretation Charts, Houston, TX (1995)
Western Atlas, Log Interpretation Charts, Houston, TX (1992)
Western Atlas, Introduction to Wireline Log Analysis, Houston, TX (1995)
Halliburton, Openhole Log Analysis and Formation Evaluation, Houston, TX (1991)
Halliburton, Log Interpretation Charts, Houston, TX (1991)
Petrophysics MSc Course Notes, paul Clover
Crain's Petrophysical Handbook, 2014
Glossary of Exon Mobil
