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Well Logging and Its
Implication in
Reservoir Simulatio
Submitt
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Group Members
Name Roll no.
Satyam Prasad 10BPE-012Yakshender 10BPE-014
Utkarsh Bhushan 10BPE-017
Nimish Newatia 10BPE-018
R. Vellayan 10BPE-024
Disha Sahoo 10BPE-058
Krishnaraj Singh 10BPE-079
Prashant Kumar 10BPE-087
Sumantha Reddy 10BPE-097
Aman Dhanani 10BPE-100
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What is well Logging?
Well log is a continuous record of
measurement made in bore holerespond to variation in some
physical properties of rocks through
which the bore hole is drilled.
Traditionally Logs are display on
girded papers shown in figure.
Now a days the log may be taken as
films, images, and in digital format.
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History
Key Events in history:
1912Conrad Schlumberger give the idea of using electrical measurem
map sub-surface rock bodies.
1919ConradSchlumberger and his brother Marcel begin work on we
1927First electrical resistivity well log was taken.
1930Dip Meter log were developed.
1936Photographic-film recorder was developed.
1941Gamma Ray and Neutron Log were used for first time.
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Why Are Well Log So Important?
They Help us to:
To Identify Reservoir Rocks
To identify the productive zones of hydrocarbon.
To define the petro-physical parameters like porosity, permeability, hyd
To measure hydrocarbon mobility.
To identify fluid saturation in reservoir.
To determine depth, thickness, formation temperature and pressure of a
To analyze various other geological parameters like formation dip.
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Open Hole Logging
Open-Hole logging refers to logging operations that are performed on a
the wellbore has been cased and cemented. In other words, the logging
through the bare rock sides of the formation.
This is the most common type of logging method because the measuremobstructed and it's done during or after the well has been drilled.
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Cased Hole Drilling
Cased-Hole logging involves retrieving logging measurements through th
or the metal piping that is inserted into the well during completion operatiohole logging is performed more rarely but still provides valuable informati
well.
Cased-hole logging is used to help operators obtain additional information
reservoir that has already been completed.
Cased-hole logging can be used to evaluate the formation and completion o
well as determine the state of the cement, corrosion and perforation
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Production Logging
Production logging denotes that area of well logging concerned with two g
problem well diagnosis, and reservoir surveillance.
Production logs are for analyzing wells already in production, with knownin place, or for looking for accessibility to inject to create drive mechanism
Logging in exploration uses the same concept, but those logs are looking aformation to see if it is conducive to hydrocarbon production.
The purpose of logging is to track fluid movement within or behind pipe othe movement of reservoir fluid contacts.
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Characterization of Well-Log
Logs are recorded to measure different physical parameter of the well.
also known as the electronic eye of the well.
Depending upon need many different parameters are considered, howe
a very few basic parameters, which are broadly classified as:
Resistivity log.
Porosity/ Radioactive log.
Sonic/ Acoustic log.
Sampling and coring.
Cement/ Mud evaluation log.
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Open Hole Logging
There are various logging tools available to evaluate the sub-surface conditions in
namely they are:
Porosity logs.To determine porosity of sub-surface rock of
interest.
Permeable zone logs.
Evaluate the permeable zone.
Resistivity logs.
Electric resistivity in the formation.
Spectral logs.
Content of special radioacti
Dipmeter and related logs.
High resolution resistivity gbedding and cracks
Caliper logs.
Borehole diameter and its s
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Gamma Ray Log
The Gamma Ray log is a continuous measurement of thenatural radioactivity emanating from the formations.
It works on the principle that clay particles containsmore concentration of high radioactive materials andhence shales show high radioactivity due to presence ofisotopes emitting radiation are Potassium-40, Uranium,and Thorium (K40, U, Th).
Sensitive detectors count the number of gamma rays perunit of time
Recorded in API Units which is 1/200th of thecalibrated, standard response.
This log can be used in all open hole cased hole andproduction logging.
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Self-Potential Log
The spontaneous potential tool records the naturally
occurring electrical potential produced.
The SP curve reflects a difference in the electrical
potential between a movable electrode in the borehole
and a fixed reference electrode at the surface
Though the SP is used primarily as a lithology indicator
and as a correlation tool, it has other uses as well.
permeability indicators.
shale volume indicator
porosity indicator, and
measurement of Rw.
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Caliper Log
Used to measure the variation of borehole diameter with depth.
Give the bore hole cross-sectional variation.
It is one of most simple tools.
Application:
High-resolution Lithology discrimination
Depth calibration of different log suites
Fracture identification Measurement of borehole rigidity.
Estimation of mud cake thickness.
The evaluation of temperature and CBL logs in combination with caliper data
help to diagnose quality of cementation
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Resistivity Log
Working Principle: The resistivity of a substance is its ability to impede the
electric current through the substance.
Formation resistivity general range 0.2 to 1000 ohm meter.
For a formation with oil or gas, both are which electrical insulators resistiv
function of formation factor, brine resistivity and water saturation.
Types (depending on environment):
Latero Log.
Induction Log.
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Resistivity Logs (contd.)
Application of resistivity Log:
True formation resistivity and flushed zone resistivity
Mud filtrate invasion profile
Quick look hydrocarbon detection
Indication of producible hydrocarbon
Correlation of different formations
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Neutron Log
Working principle: Gamma ray spectrum analysis
emitted on collision of neutrons to nucleus of atoms inthe formation.
Americium-Beryllium/Neutron bulb emits neutrons ascontinuous source of energy
Neutrons collide with nucleus of atoms in formation
and looses energy. When come back to normal state,emits Gamma ray.
Analysis of Gamma ray spectrum identifiescomposition of elements into the formation viz. C, H,Cl, O, etc.
Source: R
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Neutron Log (Contd.)
Advantages of Neutron Log:
Determination of Porosity
Lithology identification
Water saturation
Gas detection
Location and monitoring of gas/oil and water/oil contacts.
Correlation with open hole resistivity logs
Shale indicator
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Sonic/Acoustic Log
Working principle: time difference measurement to travel
an acoustic wave through on foot formation.
It is ensured the wave travels along a parallel path to the
borehole
The time difference measured is reciprocal of the
velocity of compression sound wave.
Wyllie proposed the following empirical relation fordetermination of porosity form the sonic log.
Source: Referen
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Sonic/Acoustic Log (Contd.)
Advantages:
Effects of cement coverage can be
easily measured by comparing both
open and case hole dia.
Detection of hydrocarbon in high
porosity sand.
Lithology can be identified.
Integrated travel time useful in
seismic interpretation.
Limitations:
In unconsolidated forma
formation fractures.
Provides less working e
presence of Gas saturati
aerated mud.
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Density Log
Principle: Measurement of formation bulk density and photo
electric absorption index of the lithological column.
The density depends on fluid density and matrix density in porousformation.
The detectors measure the gamma rays flux resulting from
scattering and absorption effect of the formation.
The higher the formation density, the lower the gamma rayintensity at the detectors.
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Cased Hole Logging
There are various tools available like:
Casing Collar Locator Log Locates the casing collar.
Cement Bond Logging Tool. Evaluate cement bonding.
Perforation Tool. For controlled explosion.
Bridge Plug Setting Tool.To plug the casing to isolate it.
Tubing Puncture.
To puncture the tube.
Casing cutting/ Tubing C
Sub-surface cutting of cas
String Shot.
Acid Job.
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Casing collar locator Tool
It is a magnetic device that detects changes in metal mass, such as
those induced by the relatively high mass of casing collar vis--visthe casing.
The disturbance to the magnetic field is detected as a voltagedifference
The CCL detects changes in metal volume a it moves through thetubing or casing.
Purpose: to determine the location of casing collars
Application: Depth correlation
Source: Refere
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Cement Bond Tool
It evaluates cement bond integrity.
It has single Omni-directional acoustic transmitter and two receivers. O3ft and other at 5ft.
It works based upon the principle of sonic wave-train attenuation, detec
the amplitude of a sonic signal passing along the casing as an analog
waveform.
Signal is reduced where the casing is bonded to the cement. Clearlyidentifying cement bond.
Purpose: Cement bond integrity is requisite to hydraulic isolation
Application: Cement bond evaluation
Source:
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Perforation Tool To establish fluid communication between well bore and formation for
injection.
Uses high explosives with shaped charges.
Perforators uses
Initiator/ Detonator
Detonating chord
Shaped Charges
Types:
Overbalanced method (+ve head)
Underbalanced method (- ve head)
Source: Refere
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Bridge plug setting by wire line
Bridge plug are mainly used for isolation of zones in casing
This prevent the movement of fluid from either direction.
Back off services Some times the drill string or tubing gets stuck in bore hole
A shock at a joint just above free point is given
When detonating chord is fired it releases string
Puncture Job
It is a perforation operation with specially design small change so as to have big h
depth of penetration.
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Production Logging
Various types of tools used in production logging are basically:
Radioactive fluid density tool
Production gamma ray tool
Capacitance temperature flow meter
Caliper Log
Temperature Tool Log.
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Radioactive Fluid Density Tool
Working principle: The density tool responds to electron density of the fluid in
Used to differentiate the various types of fluid in the bore-hole depending on t Tool measures borehole fluid density by radioactive techniques.
Part of the fluid flow passes through the tool between low activity Cs 137 gam
a Scintillation gamma ray detector.
An increase in the average fluid density in the sample volume causes a reducti
counts.
Purpose: Is to measure fluid density of a sample as it flows through the tool
Applications:
Multiphase production drilling
Fluid identification
Horizontal/ Highly deviated wells
High fluid flow rates.
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Production Gamma Ray Tool
It comprise a sodium iodide scintillation crystal and
photomultiplier to measure incident gamma radiations. Single conductor passing through the tool carries telemetry and
power.
The detector is unshielded and will thus accept radiation from
any direction.
Purpose:
Lithology identification and depth correlation
Gravel pack density monitoring
Evaluation of shale volume.
Delineation of nonradioactive mineral including coal beds.
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Capacitance Temperature Flow meter
Purpose: to provide a continuous log of fluid capacitance (water hold up
temperature, flow-rate and flow direction
Application:
Fluid composition form average dielectric constant
Fluid ID from temperature response
Location of leaks and cross-flow by temperature response
Production and injection log interpretation
Cement top determination
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Temperature Logging
Oldest type of production log to measure temperature.
Early thermometers have mercury as the sensing element whose expansi
contraction positioned a floating piston.
Later the sensors were replaced by vapor pressure type detectors.
This type of thermometers comprises of a bulb filled with volatile liquid
vapor pressure changes with temperature.
This is still in use mainly for bottom-hole temperature measurements.
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Reservoir Simulation
It is a practice for preparing a model of the reservoir existing below t
subsurface and defining parameters such as porosity and permeabilityetc. for every point in the reservoir.
Done by combining physical, mathematical, geological data by comp
programming
Needed to obtain performance predictions for a hydrocarbon reservoi
different operating conditions.
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Modeling Methods
Divide the reservoir into small cubes.
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Reservoir Structure
Each small cube is analyzed by different techniques.
The techniques are dependent on the scale of the cube size.
Different scales are as follows:
1. Giga Scale
2. Mega Scale
3. Macro Scale
4. Micro Scale
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Scaling
Giga Scale: Includes information associated with geophysical techni
reservoir architecture. Theories of regional characterization such as ptectonics provide an intellectual framework.
Mega Scale: It is the scale of reservoir characterization and include wwell testing and 3D seismic analysis
Macro Scale: It focuses on data sampling at the level of core analysiproperty analysis
Micro Scale: Includes pore scale data obtained from techniques suchsection analysis and measurements of grain-size distribution
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Well logging and its implication in Res
Simulation
It is a technique that comes undermega scale.
The mega scale is the scale at which we begin to inte
well log and well test data into a working model of r
Well logging gives us following important data for r
simulation:
Rock type
Fluid type
Water and hydrocarbon saturation
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Logging derived parameters aiding in
characterization
LOG TYPE USED FOR
Gamma ray Rock type
Resistivity Fluid type
Density Porosity
Acoustic (Sonic) Porosity
Neutron Hydrogen Conten
Spontaneous Potential Permeable Beds
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Resistivity Logs Used for determining Rock type
Detects shale from in situ radioactivityHigh GR => Shales
Low GR => Clean sands or carbonates
Gamma Ray Logs
Used for Fluid type Measures resistivity for formation water
High resistivity => Hydrocarbons
Low resistivity => Brine
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Density Log Used for finding porosity
Measures electron density by detecting Compton scattered gamma rays. Edensity is related to formation density.
Good for detecting HC gas with low density compared to rock or liquid.Low response => Low HC gas contentLarge response => High HC gas content
Neutron log: Used to determine Hydrogen content
Fast neutrons are slowed by collisions to thermal energies. Thermal neutrcaptured by nuclei, which then emit detectable gamma rays.
Note: Hydrogen has a large capture cross-section for thermal neutrons.
Good for detecting gas.Low response => high H content
Small response => low H content
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Acoustic (sonic) log Used to measure porosity of the rocks.
Measures speed of sound in medium.
Speed of sound is faster in rock than in fluidLong travel time => slow speed => large pore space
Short travel time => high speed => small pore space
Spontaneous Potential
Used for determining permeability of beds. Measures electrical potential (voltage) associated with the movement of ions.
Low response => impermeable shales
Large response => permeable beds.
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Pressure logs (400C)To estimate flow irrigate of the bedrock which is governe
permeability of the rock, the viscosity of the liquid and
distribution of pressure.
Down hole Video Camera (80C)
Motion pictures can be taken down to 600 m depth if thetemperature is not higher than 80C. This equipment is u
studies of fractures, scaling, and casing damage hence us
geological description.
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Televiewer Detects the surroundings, detect shape, formation, fract
casing damage, and other irregularities in the well and i
surroundingsso useful in geological description.
Fluid FlowThe continuous flow-meter spinner is logged to obtain an
picture of inflow zones within the borehole hence useful
characterization.
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References
1. Principles of Applied Reservoir Simulation, John R. Franchi
2. Basic applied Reservoir Simulation by T. Ertekin, Jamal H. Abou-Kassem, and G. R. King
3. https://www.slb.com/news/inside_news/2013/~/media/Files/resources/oilfield_review/ors11
ogging.ashx
4. http://www.geo.wvu.edu/~jtoro/petroleum/15_logs.pdf
5. http://www.Usgs.gov.in
6. http://www.spec2000.net
7. http://www.Worldoil.com
8. http://www.Vniigis.bashnet.ru 9. http://www.petrolog.net
10. http://www.bittooth.blogspot.com
https://www.slb.com/news/inside_news/2013/~/media/Files/resources/oilfield_review/ors11/spr11/defining_logging.ashxhttps://www.slb.com/news/inside_news/2013/~/media/Files/resources/oilfield_review/ors11/spr11/defining_logging.ashxhttp://www.geo.wvu.edu/~jtoro/petroleum/15_logs.pdfhttp://www.usgs.gov.in/http://www.spec2000.net/http://www.worldoil.com/http://www.vniigis.bashnet.ru/http://www.petrolog.net/http://www.bittooth.blogspot.com/http://www.bittooth.blogspot.com/http://www.petrolog.net/http://www.vniigis.bashnet.ru/http://www.worldoil.com/http://www.spec2000.net/http://www.usgs.gov.in/http://www.geo.wvu.edu/~jtoro/petroleum/15_logs.pdfhttps://www.slb.com/news/inside_news/2013/~/media/Files/resources/oilfield_review/ors11/spr11/defining_logging.ashxhttps://www.slb.com/news/inside_news/2013/~/media/Files/resources/oilfield_review/ors11/spr11/defining_logging.ashx