HOANG ANH QUAN
MINISTRY OF EDUCATION
AND TRAINING
VIETNAM ACADEMY OF
SCIENCE AND TECHNOLOGY
GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY
ORGANIC CHEMISTRY
Hoang Anh Quan
DESIGN OF STABLE GRAPHENE OXIDE-COPOLYMER
NANOCOMPOSITE DISPERSION
ORIENTATED FOR EOR APPLICATION IN
HIGH-TEMPERATURE OFFSHORE RESERVOIRS
Major :
Organic Chemistry
Code:
8440114
MASTER THESIS
ORGANIC CHEMISTRY
2021
Ho Chi Minh City - 2021
MINISTRY OF EDUCATION
VIETNAM ACADEMY OF
AND TRAINING
SCIENCE AND TECHNOLOGY
GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY
Hoang Anh Quan
DESIGN OF STABLE GRAPHENE OXIDE-COPOLYMER
NANOCOMPOSITE DISPERSION
ORIENTATED FOR EOR APPLICATION IN
HIGH-TEMPERATURE OFFSHORE RESERVOIRS
Major:
Code:
Organic Chemistry
8440114
MASTER THESIS
SCIENTIFIC SUPERVISOR:
Dr. Luu Anh Tuyen
Assoc. Prof. Dr. Nguyen Phuong Tung
Ho Chi Minh City - 2021
ASSURANCE FOR MASTER THESIS
I assure you that the data and research results in this master thesis are my research work
based on documents and data that I have researched myself. Therefore, the research
results ensure the most honesty and objective. At the same time, this result has never
appeared in any other study. Any help in this thesis was thanked and reference
information such as method, data, figures, and pictures was cited clearly. The data and
results stated in the thesis are honest, if wrong, I will take full responsibility.
Ho Chi Minh city, October 31st, 2021
Learner
Hoang Anh Quan
ACKNOWLEDGMENT
Throughout the writing of this dissertation, I have received a great deal of support
and assistance.
I would first like to thank my scientific supervisors, Assoc. Prof. Dr. Nguyen
Phuong Tung and Dr. Luu Anh Tuyen, whose expertise were invaluable in
formulating the research questions and methodology. Your insightful feedback
pushed me to sharpen my thinking and brought my work to a higher level.
I would like to acknowledge my research group from Materials for enhanced oil
recovery and energy conversion Lab - Institute of Applied Materials Science, who were
always interested and enthusiastically supported me during the study period and
completed this thesis experiment.
I would also like to thank lecturers from Graduate University of Science and Technology,
for their valuable guidance throughout my studies. You provided me with the knowledge
and tools that I needed to choose the right direction and complete my dissertation.
In addition, I would like to thank my parents for their wise counsel and sympathetic ear.
You are always there for me. Finally, I could not have completed this dissertation without
the support of my friends, who provided stimulating discussions and happy distractions
to rest my mind outside of my research.
ABSTRACT
Thermostable and highly water-soluble polymers are essential for polymer flooding —
one of the most effective methods used in the enhanced oil recovery (EOR) in hightemperature (HT) offshore reservoirs. In this research, the copolymerization reaction of
acrylamide (AM) and N-vinylpyrrolidone (NVP) monomers were performed via a freeradical mechanism induced by gamma-rays (γ-rays) irradiation. The impact of input data
(the ratio and the concentration of the monomer to product-solution viscosity) was
scanned in detail and used to optimize the copolymerization conditions. The optimal
viscosity values of the polymer concentration were 0.5 wt.%. Therefore, the optimal
conditions for copolymerization were obtained at 1.7 for AM/NVP monomer ratios and
23.2 wt.% for monomers concentration. The copolymerization induced by γ-rays
irradiation in optimized conditions was then carried out, and the obtained viscosity of
0.5 wt.% of produced copolymers solutions was 5.02 cP. These results were in good
agreement with the calculated values. The obtained copolymers were then covalently
coupled with graphene oxide (GO) synthesized from natural graphite using the modified
Hummer’s method. The product nanocomposites, called GO–P(AM-NVP), were
characterized by Fourier transform infrared spectroscopy, Raman spectroscopy,
scanning electron microscopy, and gel permeation chromatography. The thermal and
chemical stabilities of brine-dispersed P(AM-NVP) copolymers annealed at 123 °C (the
WT Miocene reservoir temperature) and GO–P(AM-NVP) nanocomposite dispersion
annealed at 135 °C (the WT Oligocene reservoir temperature) for 31 days were observed
via visual inspection and viscosity testing. Results indicated that the dispersions of
P(AM-NVP) copolymers and P(AM-NVP) copolymers conjugated on GO nanosheets
have excellent thermal and chemical stabilities and hence became a promising agent for
EOR in HT offshore reservoirs.
GRAPHICAL ABSTRACT
Hoang Anh Quan – Master thesis
Contents
CONTENTS
CONTENTS .........................................................................................................i
LIST OF FIGURES ............................................................................................ iv
LIST OF TABLES............................................................................................. vii
LIST OF ABBREVIATION.............................................................................. viii
INTRODUCTION ............................................................................................... 1
Chapter 1: Literature Review .............................................................................. 3
1.1. Enhanced oil recovery (EOR) ........................................................................ 3
1.1.1. Introduction to Enhanced oil recovery ...................................................... 3
1.1.2. Mechanism of enhanced oil recovery ....................................................... 4
1.1.3. Enhanced oil recovery methods ............................................................... 7
1.2. Polymers ..................................................................................................... 8
1.2.1. Introduction ........................................................................................... 8
1.2.2. Polymers in EOR ................................................................................... 9
1.2.2.1. Biologically produced polymer (biopolymer) ...................................... 9
1.2.2.1. Synthetic polymer........................................................................... 10
1.2.3. Synthesis of EOR polymers ................................................................... 11
1.2.5. Mechanism of polymer flooding in EOR process..................................... 14
1.2.5.1. Capillary Number (Nc ) .................................................................... 14
1.2.5.2. Polymer flooding in EOR ................................................................ 15
1.2.6. Gamma-rays irradiation-induced copolymerization.................................. 17
1.2.6.1. Free radical copolymerization .......................................................... 17
1.2.6.2. Radiation-initiated polymerization ................................................... 18
1.3. GO–Polymer materials ............................................................................... 19
1.3.1. P(N-vinylpyrrolidone–Acrylamide) copolymers ...................................... 19
1.3.1.1. Acrylamide .................................................................................... 19
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Contents
1.3.1.2. N-vinylpyrrolidone ......................................................................... 20
1.3.2. Graphene oxide in EOR ........................................................................ 21
1.3.3. The researches about GO–Polymers materials ......................................... 22
1.3.4. The researches about GO–Popolymers materials in EOR ......................... 23
Chapter 2: Experimental ................................................................................... 25
2.1. Chemical and materials ............................................................................... 25
2.2. Equipment, instruments, software ................................................................ 27
2.3. Procedure .................................................................................................. 30
2.3.1. Graphene oxide (GO) preparation .......................................................... 30
2.3.2. Gamma-rays irradiation-induced copolymerization of AM and NVP
monomers ..................................................................................................... 31
2.3.3. Optimization ...................................................................................... 32
2.3.4. Synthesis of GO–P(AM-NVP) nanocomposite .................................... 33
2.4. Determination of the effect of the monomer composition and concentration
on copolymers yield ........................................................................................ 34
2.5. Characterization measurements ................................................................. 35
2.6. Thermal and chemical stabilities of P(AM-NVP) and GO–P(AM-NVP)
dispersions ...................................................................................................... 35
Chapter 3: Results and Discussion ..................................................................... 37
3.1. Effect of monomer composition and concentration on product yield, molecular
weight, and product viscosity............................................................................. 37
3.2. Optimization .............................................................................................. 40
3.3. Characterization of P(AM-NVP) and GO–P(AM-NVP) ................................. 42
3.3.1. FTIR of GO, P(AM-NVP) and GO–P(AM-NVP) .................................... 42
3.3.2. Raman spectra of GO and GO–P(AM-NVP) ........................................... 45
3.3.3. SEM analysis of P(AM-NVP) and GO–P(AM-NVP) ............................... 46
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Hoang Anh Quan – Master thesis
Contents
3.4. Evaluation of thermal and chemical stabilities of P(AM-NVP) copolymers and
GO-P(AM-NVP) dispersions ............................................................................. 48
3.4.1. Observing the appearance after being annealing ...................................... 49
3.4.2. The viscosity of annealed samples ......................................................... 50
Chapter 4: Conclusions and Recommendations .................................................. 52
4.1. Conclusions ............................................................................................... 52
4.2. Recommendations ...................................................................................... 53
LIST OF PUBLISHED PAPERS RELATED TO LEARNER ............................ 54
REFERENCES.................................................................................................... a
APPENDIX ......................................................................................................... e
A.1. Pictures of the equipments and instruments .................................................... e
A.2. Pictures of the softwares ...............................................................................i
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Hoang Anh Quan – Master thesis
List of Figures
LIST OF FIGURES
Figure 1.1. Oil recovery categories ......................................................................... 4
Figure 1.2. Target for different crude oil systems ..................................................... 5
Figure 1.3. Effect of Nc on residual oil saturation..................................................... 6
Figure 1.4. Enhanced oil recovery methods ............................................................. 8
Figure 1.5. Suitable monomers for free radical polymerization................................ 12
Figure 1.6. The mechanism of free radical formation of KPS .................................. 12
Figure 1.7. Mechanism of pre-irradiation polymerization ....................................... 13
Figure 1.8. Mechanism of direct irradiation polymerization .................................... 14
Figure 1.9. Effect of capillary number on residual oil saturation and oil recovery ..... 15
Figure 1.10. Water breakthrough can be delayed and sweep efficiency improved by
increasing the viscosity of the injected fluid with polymer ....................................... 16
Figure 1.11. Acrylamide powder (a), structure of acrylamide (b) and polyacrylamide (c)
.......................................................................................................................... 19
Figure 1.12. Reaction formula of hydrolysis of polyacrylamide............................... 20
Figure 1.13. Structure of N-vinylpyrrolidone ......................................................... 21
Figure 1.14. Structure of graphene and graphene oxide .......................................... 21
Figure 2.1. Synthesis procedure of GO ................................................................. 31
Figure 2.2. Shortened steps of the γ-ray induced free radical P(AM-NVP)
copolymerization ................................................................................................. 32
Figure 2.3. Synthesis procedure of GO–P(AM-NVP) nanocomposite ...................... 34
Figure 3.1. P(AM-NVP) copolymers after purifying (a) and P(AM-PVP) copolymers
disperse in brine (b) ............................................................................................ 37
Figure 3.2. Response surface of viscosity of 0.5 wt.% copolymers solution .............. 41
Figure 3.3. FTIR spectra of (a) P(AM-NVP), (b) NVP and (c) AM ......................... 43
Figure 3.4. FTIR spectra of (a) GO–P(AM-NVP), (b) P(AM-NVP) and (c) GO........ 44
Figure 3.5. Raman spectra of (a) GO and (b) GO–P(AM-NVP)............................... 46
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Hoang Anh Quan – Master thesis
List of Figures
Figure 3.6. SEM images of P(AM-NVP) copolymers [(a) and (b)] and GO–P(AM-NVP)
nanocomposite (c) ............................................................................................... 46
Figure 3.7. Scanning electron microscopy energy-dispersive X-ray spectroscopy (SEMEDX) of GO-copolymer ....................................................................................... 47
Figure 3.8. SEM mapping pictures of fracture surfaces of (a) GO–P(AM-NVP) and
elemental mapping images of GO–P(AM-NVP) for (b) oxygen, (c) carbon, (d) nitrogen
.......................................................................................................................... 48
Figure 3.9. GO–P(AM-NVP) nanocomposite after free-drying (a) GO–P(AM-NVP)
disperse in brine (b) ............................................................................................. 48
Figure 3. 10. Viscosity of (a) 0.5 wt.% P(AM-NVP) copolymers in brine annealed at
123 °C and (b) 1.0 wt.% GO–P(AM-NVP) nanocomposite in brine annealed at 135 °C
during 31 days..................................................................................................... 51
Figure A.1. Powersonic 603 Hwashin Technology .................................................. e
Figure A.2. Drying/Oven – Shellap ........................................................................ e
Figure A.3. Digital Temperature Control Hotplate with Magnetic Stirrer ................... e
Figure A.4. Ultrasonic Hielscher UP 100H.............................................................. f
Figure A.5. FreeZone 6L Benchtop Freeze Dry Systems .......................................... f
Figure A.6. pH/ORP Mettler Hana HI 3220............................................................. f
Figure A.7. Brookfield DV-III Ultra ....................................................................... g
Figure A.8. Stuart RE300 Rotary Evaporator........................................................... g
Figure A.9. Fourier transform infrared spectroscopy (FT-IR) PerkinElmer frontier ..... g
Figure A.10. DSC-3/TGA Mettler Toledo ............................................................... h
Figure A.11. Raman Horiba Xplora One ............................................................... h
Figure A.12. StatGraphics 18–X64 software.............................................................i
Figure A.13. Origin 8.5 software .............................................................................i
Figure A.14. Mendeley Desktop..............................................................................j
Figure A.15. MathType 7 software ..........................................................................j
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Hoang Anh Quan – Master thesis
List of Figures
Figure A.16. Chemdraw Professional 16.0 software ................................................. k
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Hoang Anh Quan – Master thesis
List of Tables
LIST OF TABLES
Table 2.1. Chemical and materials used for experiments ......................................... 25
Table 2.2. The ingredient and properties of brine ................................................... 27
Table 2.3. Characteristics of WT Miocene and Oligocene Reservoirs [58]................ 27
Table 2.4. Equipment, instruments, and software used for characterizing/researching the
obtained materials................................................................................................ 28
Table 2.5. Result of P(AM-NVP) polymerization at different irradiation dose .......... 31
Table 2.6. Experimental conditions for optimization of polymerization .................... 33
Table 3.1. Effect of monomer composition and concentration on product yield and
molecular weight ................................................................................................. 38
Table 3.2. Effect of monomer composition and concentration on product viscosity ... 39
Table 3.3. The viscosity value of 0.5 wt.% polymer solution at different polymerization
conditions ........................................................................................................... 40
Table 3.4. Results of optimization ........................................................................ 41
Table 3.5. Viscosity of optimal-condition polymer solutions at different concentrations
.......................................................................................................................... 42
Table 3.6. FTIR results of (a) P(AM-NVP), (b) NVP and (c) AM............................ 43
Table 3.7. FTIR results of (a) GO–P(AM-NVP), (b) P(AM-NVP) and (c) GO.......... 45
Table 3.8. Viscosity of GO–P(AM-NVP) nanocomposite dispersed in brine at different
concentrations ..................................................................................................... 49
Table 3.9. Appearance of P(AM-NVP) 0.5 wt.% and GO–P(AM-NVP) 1.0 wt.%
dispersions after annealing ................................................................................... 49
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Hoang Anh Quan – Master thesis
List of Abbreviation
LIST OF ABBREVIATION
EOR
Enhanced oil recovery
IOR
Improved oil recovery
OOIP
Original oil in place
IFT
Interfacial tension
APP
1-(3-aminopropyl)pyrrole
COPAM
Copolymers of acrylamide
HPAM
Hydrolyzed polyacrylamide
HTHS
High temperature and high salinity
ATBS
Tertiary butyl sulfonic acid
TAP
Thermoassociative copolymers
AM
Acrylamide
NVP
N-vinylpyrrolidone
PAM
Polyvinylpyrrolidone
APS
Ammonium persulfate
GO
Graphene oxide
rGO
Reduced graphene oxide
GONs
Graphene oxide nanosheets
NMP
N-methylpyrrolidone
RSM
Response surface methodology
FTIR
Fourier transform infrared spectroscopy
SEM
Scanning electron microscopy
GPC
Gel permeation chromatography
TGA
Thermogravimetric analysis
WT
White Tiger
P(AM-NVP)
Poly(acrylamide-N-vinylpyrrolidone) copolymers
GO–P(AM-NVP)
P(AM-NVP) copolymers covalently couple with graphene oxide
nanocomposite
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Introduction
INTRODUCTION
Energy is one of the most critical problems in the development and
sustainability of human life. Substantial amounts of energy are supplied to human
life every year by the oil industry. The world oil production is projected to peak in
2022, with the production level being increased to 3.861 million tons and decreasing
after that [1,2]. After the primary and secondary exploitation stages, approximately
70% to 75% of the original oil in place is left trapped in the reservoir [3]; because of
the compressibility of fluids and initial pressure of the reservoir, but recovering it is
always a difficult task. While in Vietnam, many major oil fields in Vietnam, such as
White Tiger, Dragon, and Dawn, have passed the peak harvesting period and their
production is rapidly declining; therefore, enhanced oil recovery (EOR) processes
(physical and chemical) should be applied to recover a part of these trapped oils to
solve this problem. Chemical EOR is a technology that involves the injection into
reservoir solutions of chemical agents, such as alkalis, surfactants, polymers or their
combinations, and recently some smart nanofluids. Among them, polymer injection
is considered to be the most effective method, which has been widely used in EOR
technology. Over time, exploiting oilfields has become increasingly tricky as
offshore reservoirs have high temperatures and injection seawater has high salinity
and hardness. Accordingly, the polymers to be used as EOR agents must be highly
soluble in seawater and highly stable at high temperatures.
Polymer testing and consultancy for plastic have automotive, aerospace,
packaging, electronics, and medical devices applications. Polymers are incredibly
diverse elements representing such engineering fields from avionics through
biomedical applications, drug delivery systems, tissue engineering, biosensor
devices, cosmetics, etc. The application of polymers and their ensuing composites is
still advancing and going up rapidly since their ease regarding manufacturing. To be
mindful that these are some of the industries in which you would see the use and
application of various polymeric materials and polymers themselves: In aircraft,
aerospace [4]; 3D printing plastics [5]; biopolymers in molecular recognition [6];
organic polymers used in water purification [7]; printed circuit board substrates [8];
green Chemicals: Polymers and Biopolymers [9]; polymers that are used in the
operation of bulletproof vests and fire-resistant jackets [10]. Polymers, together with
surfactants, are the chemicals that play an important role in oilfield operations, especially
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Hoang Anh Quan – Master thesis
Introduction
in EOR. In EOR, surfactant solution is injected into the reservoir to reduce the interfacial
tension between oil and water to wipe out the trapped oil from the reservoir rock and
thence increase the oil production. While an injection of polymer solution into the
reservoir for increasing the driving fluid viscosity to improve sweeping efficiency, and
due to that, the oil production rises. The acrylamide-based polymers have been the most
commonly used for this application. Recently, graphene oxide is also studied in EOR
because it can increase the water viscosity, reduce the interfacial tension, and
considerably emulsify the oil droplets in water [11].
In the present work, the irradiation-induced copolymerization of the AM and
NVP monomers was investigated to explore the optimal reaction conditions. The
conjugation of synthesized P(AM-NVP) copolymers on thermo-resisted GO
nanosheets was then performed to obtain GO–copolymer nanocomposites with high
viscosity, solubility in seawater, and stability at high temperature (135 °C).
Moreover, the proportion of monomers and their total content in the reaction mixture
were optimized during the material fabrication to produce a polymer product with
suitable viscosity and stability for high-temperature offshore reservoirs, which has
never been reported so far. These features render them suitable for EOR application
in HT offshore reservoirs.
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Hoang Anh Quan – Master thesis
Chapter 1: Literature review
Chapter
1
Literature Review
Chapt er 1: Li te r ta ure Revi w
e
1.1. Enhanced oil recovery (EOR)
1.1.1. Introduction to Enhanced oil recovery
According to the method and time hydrocarbons are produced, there are three
terms: primary oil recovery, secondary oil recovery, and tertiary (enhanced) oil recovery.
Primary oil recovery describes the production of hydrocarbons under the natural driving
mechanisms present in the reservoir without extra help from injected gas or water.
Secondary oil recovery refers to the additional recovery resulting from the conventional
methods of water injection and immiscible gas injection. Finally, tertiary (enhanced) oil
recovery is the additional recovery over and above what could be recovered by secondary
recovery methods. Various methods of enhanced oil recovery (EOR) are essentially
designed to recover oil, commonly described as residual oil, left in the reservoir after
both primary and secondary recovery methods have been exploited to their respective
economic limits. The concept of the three recovery categories is illustrated in Figure
1.1.
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Hoang Anh Quan – Master thesis
Chapter 1: Literature review
Figure 1.1. Oil recovery categories
1.1.2. Mechanism of enhanced oil recovery
Improved oil recovery (IOR) is a general term that implies improving oil recovery
by any means (operational strategies, such as infill drilling, horizontal wells, and
improving areal and vertical sweep). Enhanced oil recovery (EOR) is a concept being
more definitive and it can be considered as a section of IOR. EOR is the process of
reducing oil saturation below the residual oil saturation “Sor”. The target of EOR varies
considerably by different types of hydrocarbons. Figure 1.2 shows the fluid saturations
and the target of EOR for typical light and heavy oil reservoirs and tar sand. For light oil
reservoirs, EOR is usually applicable after secondary exploitation stages with an EOR
target of approximately 45% original oil in place (OOIP). Heavy oils and tar sands
respond poorly to methods in primary and secondary exploitation stages, and the
majority of the production from these types of reservoirs comes from EOR methods.
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Hoang Anh Quan – Master thesis
Chapter 1: Literature review
Figure 1.2. Target for different crude oil systems
The magnitude of the reduction and mobilization of residual oil saturation “Sor” by
an EOR process is controlled by two major factors:
- Capillary number “Nc”
- Mobility ratio “M”
The capillary number is defined as the ratio of viscous force to interfacial tension
force, or
Nc
Viscous force
v
Interfacial tension force cos
k p
Or equivalently as: N c 0
L
(1.1)
(1.2)
Where
μ = viscosity of the displacing fluid
σ = interfacial tension (IFT) between the displacing fluid and the displaced fluid (oil)
v = Darcy velocity
θ = the contact angle
= porosity
k0 = effective permeability of the displaced fluid
Δp/L = pressure gradient
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Hoang Anh Quan – Master thesis
Chapter 1: Literature review
Figure 1.3. Effect of Nc on residual oil saturation
Figure 1.3 is a schematic representation of the ratio of residual oil saturation (after
conduction of an EOR process to residual oil saturation before the EOR process) and the
capillary number. The illustration shows the reduction in the residual oil saturation with
the augmentation in the capillary number. It is clear from the Eq. (1.2) that the capillary
number can be increased by:
- Increasing the pressure gradient Δp/L
- Increasing the viscosity of the displacing fluid
- Increasing displacing fluid viscosity μ
- Decreasing the interfacial tension between the injection fluid and displaced fluid
Another significant concept in understanding the displacing mechanism of an EOR
process is the mobility ratio “M”. The mobility ratio is defined as the ratio of the
displacing fluid mobility to that of the displaced fluid:
M
displacing ( k / )displacing
(1.3)
displaced ( k0 / 0 )displaced
Where “k” is the effective permeability and “μ” is the viscosity. The mobility ratio
influences the microscopic (pore-level) and macroscopic (areal and vertical sweep)
displacement efficiencies.
A value of M > 1 is considered unfavourable because it indicates that the displacing
fluid flows more rapidly than the displaced fluid (oil). This unfavourable condition can
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