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UCSI UNIVERSITY
Faculty of Engineering, Technology and Built Environment
Chemical and Petroleum Engineering Department
Enhanced Oil Recovery
Petroleum engineering BSc program - EG412
January 2019
Lecture (1)
Chapter 1-
Introduction
3 Jan to 5 Apr 2019
First semester/fourth Years
Syllabus
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Introduction
Miscible Processes
Introduction to Enhanced Oil Recovery Methods (EOR);
Chemical
and
Polymer
Flooding
Reservoir
engineering
concepts
for EOR; Displacement
fundamentals;
Factors
affecting
oil
recovery;
Thermal
Processes
Comparative performance of different EOR methods;
Screening
criteria; Definitions:
mobility ratios,
sweeping
Microbial
Enhanced
Oil Recovery
(MEOR)
efficiencies, recovery efficiencies, trapped oil saturation;
phase behaviour and fluid properties. Secondary Drive
Mechanism (Water injection).
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Lecture outline
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Extraction of oil from reservoirs
Secondary Recovery
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Introduction
What is a Waterflood?
Why would you need to waterflood?
How does a waterflood work?
Water Flooding Mechanism
Waterflood Progression
Waterflood Recovery Potential
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Types of Oil Reservoirs More
Favorable for Waterflood
Gas Flooding Mechanism
Waterflood Conceptual Design
Predicting Waterflood
Performance
Review of water Flood : Field
Application
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Extraction of oil from reservoirs
Primary Recovery
involves the reservoir pressure causing the oil to rise
through the wellbore to the surface.
Secondary Recovery
includes immiscible displacement
techniques such as water flooding, in which injected water
displaces the oil from the sandstone or limestone into the
production wells.
Tertiary Recovery
Is a collective term for various methods of increasing oil
recoveries from reservoirs that have already undergone
primary and secondary recovery.
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Extraction of oil from reservoirs
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PRIMARY PRODUCTION
SECONDARY PRODUCTION
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Water flooding
TERTIARY RECOVERY

Thermal Methods
 Chemical Methods
 Gas Methods

Microbial Methods
 Others
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Extraction of oil from reservoirs
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Secondary Recovery
Introduction
Secondary recovery is the result of human intervention in the reservoir to
improve recovery when the natural drives have diminished to unreasonably
low efficiencies. Two techniques are commonly used:
 (i) Waterflooding
 (ii) Gasflooding
Injection of water /gas at the reservoir to;
(i) Maintain the reservoir pressure, and
(ii) Displace oil (usually with gas and water) towards
production wells.
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Secondary Recovery
What is a Waterflood?
• It is the injection of water into a wellbore to push, or
“drive” oil to another well where it can be produced.
• Recognized enhanced oil recovery technique since
early 1900’s.
• Some oil reservoirs have natural water influx, which
increases oil production.
– Called “water drive” reservoirs
– They are natural “waterfloods”
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Secondary Recovery
Why would you need to waterflood?
• MANY (majority?) oil reservoirs are solution gas
drive
• Waterflooding can recover much of the oil left behind
under “Primary” production, especially a solution gas
drive system
• Since waterflooding usually follows “primary”
production, it is often called a “secondary” recovery
technique
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Secondary Recovery
How does a waterflood work?
• Certain oil wells are converted to water injection wells
• Other oil wells remain as producers
• The injected water displaces, or “pushes” oil to the
producing wells
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Secondary Recovery
Water Flooding Mechanism
• Injection of water in the base of reservoir .
• Water flooding maintain the reservoir pressure.
• Displace oil (usually with gas and water) towards production
wells.
• The successful outcome depends on
 Designs based on accurate relative permeability data in both
horizontal directions,
 The choice of a good injector/producer array
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Secondary Recovery
Waterflood Example
WATERFLOOD OPERATIONS
PRIMARY PRODUCTION
A single 5-Spot
pattern has:
One net producer,
and one net injector,
or two total wells
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Secondary Recovery
Waterflood Progression
Time 1
Early in life of
waterflood. Producer
making 100% oil.
The effectiveness of the
water“sweeping” the area of the
pattern is called the “areal sweep
efficiency”, or Ea .
Time 2
Time 3
Still relatively early in life
of waterflood. Water
banks expanding, but
producer still making
100% oil.
Mid-life of the
waterflood. Water has
reached the producing
well. Producer now
makes oil and water.
Time 4
Late in the life of the
waterflood. Producer
now making large
volume of water
compared to the oil
volume.
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Secondary Recovery
Waterflood Recovery Potential
• Should recover an additional 10% to 40% of the
reservoir OOIP
• A term commonly used is the secondary to primary
ratio (S/P)
Primary is the expected ultimate primary oil recovery
Secondary is the incremental waterflood recovery
S/P ratio of 1+ is generally expected
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Secondary Recovery
Types of Oil Reservoirs More Favorable for Waterflood
• Shallower is better
 Cheaper drilling and operating costs
 Typically lower primary recovery
• Low energy oil (low Bo)
 Lower primary oil recovery
 Lower gas saturation
• Higher permeability is better
 Process the waterflood faster
 May utilize wider well spacing (cheaper)
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Secondary Recovery
Gas Flooding Mechanism
•
This method is similar to
waterflooding in principal, and is
used to maintain gas cap pressure
even if oil displacement is not
required.
•
Injection of a gas. e.g CO, N2 or
flue gases are generally used.
•
Categorized into two types
 Immiscible gas injection.
 Miscible or high-pressure gas
injection.
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Secondary Recovery
Gas Flooding Mechanism
Immiscible gas injection
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Inefficient fluid for additional oil
recovery.
The gas is non-wetting to
reservoir rocks
The gas will move through the
larger spaces of the reservoir
rock
Thus the initial gas may be
displacing gas not oil.
Miscible gas injection
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The gas is wetting the reservoir rock.
The gas moves through smaller
pores.
The injection of non aqueous
hydrocarbons solvent.
The displacement of oil occurs.
An important factor is that the mass
transfer between displaced and the
displacing factor/ phase.
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Secondary Recovery
Waterflood Conceptual Design
To develop a conceptual design, the engineer will need a certain
amount of data from the reservoir engineering study. The major
items needed are as follows.
1.
2.
3.
4.
5.
6.
Field name and location.
Producing formation, depth, and thickness.
Probable injection pattern and alternatives - e.g., five-spot,
nine-spot, linedrive.
Rough order-of-magnitude estimates of injection pressures
and rates.
Any information available on water sources and quality.
Any information on formation sensitivity or other pertinent
items.
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Secondary Recovery
Predicting Waterflood Performance
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Large number of methods
Each has severe limitations
Use idealized reservoirs and operating conditions
The waterflood prediction methods will be
categorized in groups that consider primarily:
1.
2.
3.
4.
5.
Areal sweep effects
Reservoir stratification
Displacement mechanism
Numerical methods
Empirical methods
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Secondary Recovery
Predicting Waterflood Performance
1. Prediction Methods Concerned Primarily with Areal Sweep
 Craig et al
 Caudle & Witte correlation
 Claridge correlation
 Mahaffey et. Al model
2. Prediction Methods Concerned Primarily with Reservoir
 Stratification
 Dykstra-Parsons Method
 Stiles Method
 Prats, et al. Method
3. Prediction Methods Concerned Primarily with Displacement Mechanism
 Buckley-Leverett Method
 Roberts Method
 Craig-Geffen-Morse Method
 Higgins-Leighton Method
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Secondary Recovery
Predicting Waterflood Performance
4. Prediction Methods Based on Numerical Models
 A complete solution to the multiphase, multidimensional partial differential
equations which govern fluid flow in a porous and permeable media is
probably the best prediction model that we can use.
 The effects of varying injection patterns, well locations, injection and
producing rates, plus many other factors, can be studied which were not
possible using previously discussed models.
 Mathematical models are very expensive to develop and run. Furthermore,
extensive amounts of data are generally required to take advantage of the
flexibility and accuracy afforded by these models.
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Secondary Recovery
Predicting Waterflood Performance
5. Prediction Methods Based on Empirical Models
 They are based on the expectation that waterfloods in reservoirs with
similar geological and depositional settings would tend to behave
similarly. In two ways:
o Predicting performance by comparison with a similar flood
o Predicting performance from the average behavior of several floods
 Many empirical techniques have been proposed in the waterflood
literature.
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Carter Method
Suder
stiles
Dykstra Parsons
Shell
U.S.B.M.Method
Pan American Method
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Secondary Recovery
Review of Water Flood : Field Application – North American Waterflood
MONUMENT BUTTE UNIT-MB FED 10-35 - Production
8.0
28000
6.0
24000
5.0
20000
4.0
16000
3.0
12000
2.0
8000
1.0
4000
0.0
1982
GOR, SCF/BO
MBBL/MONTH
7.0
32000
Oil
Wtr
Wtr Inj
GOR
0
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
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Secondary Recovery
Review of Water Flood : Field Application - Handil Oilfield, Indonesia
SPE110882
Fig: Handil Production profile
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Things I learned
Things I confirmed
Question I still have
Be ready next lecture
with my best wishes
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Introduction :
Methods to Improve Recovery Efficiency
This course will focus on Enhanced Oil Recovery Methods.
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Introduction :
Extraction of oil from reservoirs
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Introduction :Secondary recovery
Predicting Waterflood Performance
4. Prediction Methods Based on Numerical Models
A complete solution to the multiphase, multidimensional
partial differential equations which govern fluid flow in a
porous and permeable media is probably the best prediction
model that we can use.
The effects of varying injection patterns, well locations,
injection and
producing rates, plus many other factors, can be studied
which were not possible using previously discussed models.
Mathematical models are very expensive to
develop and run. Furthermore, extensive amounts of data
are generally required to take advantage of the flexibility
and accuracy afforded by these models.
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Secondary recovery
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Introduction :Secondary recovery
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Introduction :Secondary recovery
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Introduction :Secondary recovery
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Introduction :Secondary recovery
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