source rock and reservoir evaluation methods, drive mechanism

1. In the name of Almighty Allah the
most Gracious the most Merciful
Asalam_O_Alikum
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2. Group Members
Mirza Osama Baig 19-PG-11
Abdul Rafay 19-PG-14
Rahzan Ali 19-PG-15
Hazrat Zubair 19-PG-30
Abdul Rauf 19-PG-37
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3. Objectives
Source Rock
Evaluation
Reservoir
Evaluation
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4. What does Evaluation means?
Definition of Evaluation according Cambridge dictionary is,
“The process of judging or calculating the quality, importance, amount,
or value of something”
In the Petroleum industry, we evaluate the quantity and quality of HC in
Formation.
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5. Formation Evaluation
In Petroleum exploration and development, formation evaluation is used to
determine the ability of a borehole to produce petroleum. Essentially it is the
process of recognizing a commercial well when you drill one.
Source Rock
Evaluation
Reservoir
Evaluation
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We can characterize formation evaluation into two general category.
Formation Evaluation

6. What is Source Rock?
 Source rocks are fine grained organic-rich sediments from which hydrocarbons
have been generated or are capable of being generated.
 They can be found in sediments deposited in a variety of environments including
deep-water marine.
 Common examples of Source rocks include Shales and lime-mudstones, which
contain significant amount of organic matter.
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7. Source rock evaluation
Quantity of organic
matter.
Quality of organic
matter.
Thermal Maturation.
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Source Rock Evaluation can done through

8. Source Rock Evaluation
Total Quantity of
Organic matter
LECO method
Rock-Eval
pyrolysis
Loss-On-
(LOI) method
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9. LOI method
 A known weight of sample is heated to between 350º and 440ºC for ~8 hours.
 The sample is then cooled in a desiccator and weighed.
 Organic matter content is calculated as the difference between the initial and final sample
weights therefore it is also known as It is also known as Loss-On-Ignition (LOI) method .
 LOI method temperatures should be maintained below 440ºC to avoid the destruction of
any inorganic carbonates that may be present in the sample.
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10. LECO method
 This method entails the use of LECO carbon analyzer to estimate TOC.
 Samples are crushed and treated to remove carbonates of inorganic origin before
combusted in an oxygen rich environment permitting the formation of CO2 from
the carbon in the rock.
 The amount of CO2 liberated is equivalent to the organic richness of the source
rock.
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11. When the TOC in shale greater than 5% ,It is Excellent.
When the TOC in Carbonate greater than 2% ,It is Excellent.
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12. Evaluation of Source Rock
(Pyrolysis – Rock-Eval Method)
Pyrolysis is the
decomposition of
organic matter by
heating in the
absence of oxygen
after which the
richness and
maturity of
potential source
rocks are
measured.
During the process we
generate three peaks,
• S1 shows the amount of free
hydrocarbons in the sample.
• S2 shows the amount of
hydrocarbons generated
through thermal cracking of
organic matter.
• S3 shows the amount of
produced during pyrolysis of
kerogen.
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13. Qualitative Evaluation of Source Rock (Kerogen)
Microscopic/ Visual Analysis
• Kerogen is a macro-molecular complex with
a polymer-like structure that forms a
of the organic richness in a sedimentary
• Components of kerogens can be
under microscope evaluation on the basis
there structures and rings of carbons.
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14. Source Rock Characterization
• Immature (no hydrocarbon generation).
• Mature (extensive hydrocarbon generation).
• Over mature (most hydrocarbons have been
generated).
Once the parameters of a
source rock have been
substantially derived it can
then be categorized based on
its current ability (maturity) oil
generation into the following;
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15. Thermal Maturity
(Vitrinite Reflectance –VR)
Vitrinite is a part of kerogen derived from plants.
Temperature increase causes vitrinite to become reflective.
Incident light is reflected from polished samples and a reflectance value is taken.
The reflectance (Ro) of vitrinite can be used to define thermal maturity or rank of the kerogens.
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16. What is the Reservoir ?
• It has average depth of 0.5  5
• And average width is 0.1  10Km
A reservoir is a subsurface
of porous and permeable rock
that has both storage capacity
and the ability to allow fluids to
flow through it.
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17. Why Reservoir Evaluation?
The main objective for reservoir evaluation
is to understand the formation properties
of the reservoir for better decision
on the estimation of hydrocarbon volume,
assess recoverable reserves, and prioritize
development based upon the value of the
various resource classes in the asset.
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18. Reservoir Evaluation Methods
Reservoir Evaluation
Direct method
volumetric methods
Indirect method
material balance
methods
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19. Reservoir Evaluation
(Direct Method)
Volumetric provide a static measure of oil or gas in place.
Accuracy of volumetric
depends on data for:
Porosity.
Net
thickness.
Areal extent.
Hydrocarbon
saturations.
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20. Volumetric Analysis
Also known as the geologist's method
because it is based on geological maps, core
logs and analysis of wireline logs.
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21. Reservoir Evaluation
(Indirect Method)
Material balance methods provide a dynamic
measure of hydrocarbon volumes.
Accuracy
depends on
quality of data
for:
Pressure
Surveys
Temperatur
e Surveys
Analysis of
Recovered
Fluids
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22. Drive Mechanism
Material balance methods involve estimation of
reservoir recovery from the PVT behavior of the
reservoir and contained fluids.
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23. Reservoir Drive Mechanism
Reservoir Drive Mechanism
Solution Gas
Drive (or
Depletion
Drive)
Gas Cap
(and Gravity
Drainage)
Natural Water
Drive
Compaction
Drive
Combination
Drive
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24. Solution Gas Drive
The principle of solution gas drive or depletion drive is the
expansion of dissolved gas and liquid oil in response to a
pressure drop.
The change in fluid volume results in production.
Dissolved gas reservoirs typically recover between 5 and
OOIP( original oil in place) and 60 to 80% GIIP( gas in
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25. Gas Cap Drive
The principle of
gas cap drive or
depletion is the
expansion of
gas and in
response to a
pressure drop.
Gas cap drive
reservoirs
typically recover
20 to 40% OOIP,
sometimes as
high as 60%.
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26. Gas Cap Drive Mechanism
Gas cap expansion maintains the pressure in the oil leg.
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27. Natural Water Drive
The principle of natural water drive is that an aquifer provides
the energy for hydrocarbon production.
Both water expansion as a result of pressure reduction and
inflow are involved.
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28. Natural Water Drive
Natural water drive is associated with high recovery rates, oil from 35-75% OOIP,
gas from 60-80% GIIP.
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29. Compaction Drive
In compaction drive, the energy for oil production is provided by
the collapse of the porous medium skeleton and expansion of
pore fluids when the reservoir pressure drops.
The increase in the "grain pressure" or effective stress causes
collapse and compaction (consolidation) of the reservoir.
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30. Compaction Drive
This drive
mechanism is
common in highly
compressible,
unconsolidated
reservoirs
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31. Combination Drive
In combination
drive reservoirs,
at least two of
the basic drive
mechanisms are
active in
expelling oil:
solution gas
exsolution
gas cap
expansion
natural
water influx
pore
collapse
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32. Combination Drive
 The example shows a combination of natural water influx and gas cap drive.
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33. Drive Mechanism Conclusion
 Ultimate oil and gas recoveries vary depending on the drive mechanism. For oil,
water drive is most effective.
 Typical primary recoveries are in the 25-40% range (maximum 75%).
 For gas, gravity drainage, water drive and depletion drive can provide > 80%
recovery.
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