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Petroleum Science and Technology

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Evaluation of the ability of the hydrophobic
nanoparticles of SiO2 in the EOR process through
carbonate rock samples
Mohammad-Ali Ahmadi, Zainal Ahmad, Le Thi Kim Phung, Tomoaki
Kashiwao & Alireza Bahadori
To cite this article: Mohammad-Ali Ahmadi, Zainal Ahmad, Le Thi Kim Phung, Tomoaki
Kashiwao & Alireza Bahadori (2016) Evaluation of the ability of the hydrophobic nanoparticles
of SiO2 in the EOR process through carbonate rock samples, Petroleum Science and
Technology, 34:11-12, 1048-1054, DOI: 10.1080/10916466.2016.1148052
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Published online: 12 Jul 2016.

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Date: 22 July 2016, At: 01:23


PETROLEUM SCIENCE AND TECHNOLOGY
, VOL. , NOS. –, –

/>
Evaluation of the ability of the hydrophobic nanoparticles of SiO in
the EOR process through carbonate rock samples
Mohammad-Ali Ahmadia , Zainal Ahmadb , Le Thi Kim Phungc , Tomoaki Kashiwaod ,
and Alireza Bahadorie

Downloaded by [University of California, San Diego] at 01:23 22 July 2016

a

Department of Petroleum Engineering, Ahwaz Faculty of Petroleum Engineering, Petroleum University of Technology,
Ahwaz, Iran; b School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, Nibong
Tebal, Penang, Malaysia; c Department of Chemical process and Equipment, Faculty of Chemical Engineering, Hochiminh
City University of Technology, Hochiminh City, Vietnam; d Department of Electronics and Control Engineering, National
Institute of Technology, Niihama College, Yagumo-cho, Niihama, Ehime, Japan; e School of Environmental Science and
Engineering, Southern Cross University, Lismore, Australia

ABSTRACT

KEYWORDS

More than 50% of oil remains in reservoirs after primary and secondary recovery processes. Consequently, methods of enhanced oil recovery (EOR) should
be applied for more recovery from these reservoirs. In this study the ability of
hydrophobic nanoparticles of sio2 in EOR process through carbonate rock samples is studied. By employing hydrophobic nanosilica, we can lower interfacial
tension between oil and nanofluid and then reduce the mobility ratio between
oil and nanofluid in carbonate reservoirs; however, nanosilica can increase the
viscosity of water exponentially. To evaluate this goal, core displacement experiment for carbonate core is conducted. These experiments are performed on
the carbonate samples saturated with oil and brine that had got injected with
nanosilica with six different concentrations. Investigating the outcomes shows
that by rising nanoparticle concentration, the IFT between water and oil phases

decreases and yields in decrease the mobility ratio between oil and nanofluid.
For this, we measure the recovery level in different states of using 0.05, 0.1,
0.1, 0.15, 0.3, 0.6, 1.0, and 0 concentration of the nanoparticle. The outcomes
achieved from our experiments reveals that employing hydrophobic nanosilica could increases the oil recovery factor.

Carbonate reservoir;
hydrophobic; microemulsion;
nanoparticle; oil reovery

1. Introduction
Nanoscale science and technology is a young field that covers nearlyevery discipline of science and engineering. The research on nanotechnology is evolving and expanding in such a rapid pace that the existing
and potential applications can be considered almost endless. An emerging application of nanotechnology
in oil reservoir engineering is developing new types of nanofluids for EOR, drilling, and so on. Nanofluids are colloidal suspensions of nanoparticles in a base fluid, which is commonly water or organic liquids.
These fluids are prepared by introducing small volumetric fractions of nanoparticles into the liquid phase
in order to enhance or improve some of the fluid properties. Recent investigations revealed that nanomaterials have impressive characters for engineering applications. Moreover, nanofluids can be designed to
be compatible with reservoir fluids/rocks and be environmentally friendly, and they may show improved
transport through micro-channels in porous media (Evdokimov et al., 2006; Singh et al., 2010; Xiangling
and Ohadi, 2010). Investigation of applicability of nanotechnology in EOR processes has received a great
CONTACT Alireza Bahadori

School of Environmental Science and Engineering, Southern Cross
University Lismore Australia.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lpet.
©  Taylor & Francis Group, LLC


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PETROLEUM SCIENCE AND TECHNOLOGY

1049

deal of attention in recent years. The first requirement for application of nanoparticles in EOR processes
is their ability to travel easily through the rock porous media i.e. with minimal retention and formation
damage. Therefore the transport properties of nanoparticles in porous media have been considered a
basic issue for many studies. Rodriguez et al. (2009) studied the transport properties of surface-treated
silica nanoparticles, by injecting concentrated suspensions of the nanoparticles into sedimentary rocks
of different lithologies and permeabilities. Their observations indicate a weak, reversible attachment of
particles to pore walls. Yu et al. (2010) introduced paramagnetic nanoparticles as potential EOR agents,
which can be used in EOR processes to control the behavior of injected fluids by imposing an external
field, or can be used to evaluate oil saturations and other properties of an EOR target formation.
Kanj et al. (2009) carried out a series of core flood experiments to investigate the transport of nanoparticles in reservoir rocks and to identify the limiting size of nanoparticles to be used as in situ reservoir
agents in the ARAB-D formation. There have been some attempts to use nanoparticles to change wettability of reservoir rock. Considering the micrometer scale of pore diameters in reservoir rock. Adsorption
of hydrophilic particles on the porous walls of an oil-wet reservoir rock can change it into a water-wet
rock. This will result in an increase in the relative permeability of the oil phase and thus a decrease in
the relative permeability of the water phase and a decline in the water cut after water breakthrough.
Adsorption of particles with neutral wettability on porous walls will eliminate surface tension (Ju et al.,
2002).
Ju et al. (2002) reported nanometer polysilicon materials that could change the wettability of porous
surfaces. Using experimental data, they developed a mathematical model and a simulator to simulate
water injection dynamics under the conditions of hydrophobic polysilicon injection.
Later, Ju et al. (2006) studied the mechanism of EOR using hydrophilic polysilicon nanoparticles for
changing the wettability of porous media. The results of numerical simulation showed that porosity and
permeability would decline due to retention of hydrophilic polysilicon during its transport in porous
media. It was also shown that oil recovery can be enhanced obviously by flooding with suspension of
hydrophilic polysilicon; polysilicon concentration of 2.0–3.0% by volume has been suggested for improving oil recovery (Ju et al., 2006). The mathematical model for transport and wettability alteration effect
of both hydrophilic and hydrophobic polysilicon types have been later presented in another publication;
the results of which have been shown to have good match with experimental data (Ju and Fan, 2009).
Di et al. (2010) used injection of solutions containing hydrophobic nanoparticles of SiO2 . Their experimental observations showed that the hydrophobic nanoparticles of SiO2 could be adsorbed tightly on
the surface of the porous wall to form a strong hydrophobic layer. The core displacement experiments

conducted on four core samples showed that the water-phase effective permeabilities of all cores after
the treatment with hydrophobic nanoparticles increase, but at different rates. An average increase in
water-phase effective permeability has been reported to be about 47% for the tested core samples, which
clearly shows that the flowing resistance of rock’s micro-channels decreases greatly after-treatment with
hydrophobic SiO2 nanoparticles (Di et al., 2010). Skauge et al. (2010) investigated the oil mobilization
properties of nanosilica particles through the mechanism of microscopic flow diversion by log jamming,
which involves pore blocking and diversion of injection fluids in microscopic pore scale. They used core
floods by well-defined nanosized silica particles to investigate the oil mobilization properties of the silica
nanoparticles and made a comparison with polymer floods and the combination of polymer and silica
particles. They used AEROSIL MOX 80 silica particle type with a concentration of 300 ppm for core
flood experiments. This paper highlights the behavior of hydrophobic nanosilica in aqueous solutions
as agent to be implemented for EOR schemes in carbonates. Displacement of the studied hydrophobic
nanosilica was assessed using a core flooding apparatus.

2. Experimental
2.1. Materials
In this work AEROSIL R816 was employed as hydrophobic nanosilica, which is made from SiO2 and
an additive. Figure 1 depicts the image of AEROSIL R816 under TEM. It is worth to mention that


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1050

M.-A. AHMADI ET AL.

Figure . The image of silica nano particles observed under TEM.

AEROSIL R816 purchase from Degussa Company. Physical properties of AEROSIL R816 are demonstrated in Table 1. Thickening and thixotropic effects of nanosilica at a given concentration depend to a
great extent on the intensity of the dispersing. Therefore the dispersion method is of crucial importance.

As recommended by the producing companies, good results are achieved with ultrasonic homogenizer.
An ultrasonic homogenizer (UT-1200) has been used in this study to disperse the nanosilica particles in
the aqueous media. The silica powder was weighed, wetted by the dispersing media (i.e., water) and then
dispersed using the ultrasonic homogenizer for more than 5–6 h. A master suspension of fumed silica in
water with a concentration up to 5 wt% was prepared initially and suspensions with lower concentration
were prepared by diluting the master suspension with distilled water, either with or without the master
surfactant solution.
The characterization of the crude oil employed in this study is reported in Table 2. Six different carbonate core samples were employed in this research and characterization of the aforementioned rock
samples are illustrated in Table 3.
2.2. Core Displacement
This section summarizes the core flooding experiments. A comprehensive series of high-pressure hightemperature (HPHT) core displacement experiments were carried out. The experiments are done on
different carbonate samples when they are water-wet. They were about 10 cm long and 3.6 cm diameter.
Table . Physical properties of nanoparticles.
AEROSIL R 
Behavior with respect to water
Appearance
BET-surface area, m /g
Average primary particle size, nm
Tapped density, g/L
SiO , wt%
Al O , wt%
Fe O , wt%
TiO , wt%
HCl, wt%

Partially hydrophobic
Fluffy white powder
 ± 



ࣙ.
ࣘ.
ࣘ.
ࣘ.
ࣘ.

Reprinted with permission from Ahmadi, M. A., and Shadizadeh, S. R. (). Adsorption of novel nonionic surfactant and particles
mixture in carbonates: enhanced oil recovery implication. Energy and Fuels :–. Copyright  American Chemical Society.


PETROLEUM SCIENCE AND TECHNOLOGY

1051

Table . Composition of reservoir oil used in this study.

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Dead oil
Component

mol%

wt%

HS
CO
N
C
C

C
IC
NC
IC
NC
C+
M.W C+
S.G C+

.



.
.
.
.
.
.
.

.

.



.
.
.

.
.
.
.

All the core flooding experiments were performed at 100°C. The core holder overburden pressure was
maintained at 1500 psig and rate of injection at all tests fixed at 0.1 cc/min.

3. Results and Discussion
Core displacement experiments were performed for different concentrations of hydrophobic nanosilica.
Figure 2 illustrates the curve of oil recovery factor versus corresponding injected pore volume via different concentrations of hydrophobic in core displacement experiments. To produce the remaining and
residual oil from reservoir rock by water injection method we should reduce interfacial tension between
oil and water because reducing the IFT results reducing the capillary pressure and consequently more oils
can be produced. Furthermore, to avoid the fingering phenomenon in water injection we should reduce
the mobility ratio between injection fluid and oil and to assess this goal we should increase viscosity of
the injection fluid. Hydrophobic nanosilica can reduce interfacial tension between oil and water along
with increasing the viscosity of water (Ahmadi and Shadizadeh, 2014). Two main phenomena that contributed in oil production during nanoflooding are IFT reduction and increasing viscosity of solution.
Figure 2a shows curve of oil recovery factor (RF) versus relevant injected pore volume of brine. As
clear be seen from Figure 2a brine flooding can improve the ultimate RF up to 55.45% of OOIP. Figure 2b
depicts the variation of oil recovery factor against corresponding injected pore volume of 500 ppm of
hydrophobic nanosilica. As demonstrated in Figure 2b, by employing 500 ppm nanosilica in water phase
the ultimate oil recovery factor increased to 57.24% of OOIP. Figure 2c illustrates the changing of oil
recovery factor versus relevant nanofluid injected pore volume for 1000 ppm of hydrophobic nanosilica.
As depicted in Figure 2c, via 1000 ppm of nanosilica in water phase the oil recovery factor increased and
an ultimate RF raised to 61.23% of OOIP. One of the reasons for this fact is lowering the interfacial tension
between two immiscible phases (water and oil) and then reducing the mobility ratio between nanofluid
Table . Core characterization which used in this study.

Core name
G

G
G
G
G
G

Length, cm

Average diameter,
cm

Area, cm

.
.
.
.
.
.

.
.
.
.
.
.

.
.
.

.
.
.

Bulk volume,
cm
PV (Sw = ), m
.
.
.
.
.
.

.
.
.
.
.
.

Porosity, %

Absolute
permeability,
mD

.
.
.

.
.
.

.
.
.
.
.
.


M.-A. AHMADI ET AL.

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1052

Figure . Oil recovery (%OOIP) as a function of volume injected for (a) brine flooding, (b) nanoflooding at  ppm, (c) nanoflooding at
 ppm, (d) nanoflooding at  ppm, (e) nanoflooding at  ppm, (f) nanoflooding at  ppm, and (g) nano flooding at 
ppm).


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PETROLEUM SCIENCE AND TECHNOLOGY

1053

Figure . Relationship between ultimate recovery (%OOIP) and nanosilica concentration (ppm).

and oil; however, another important reason is increasing the viscosity of water phases by adding nanosilica to injected fluid. Figure 2d depicts the variation of oil recovery factor versus corresponding nanofluid
injected pore volume with concentration of 1500 ppm hydrophobic nanosilica. Figures 2d–g show the
changing of oil recovery factor versus relevant nanofluid injected pore volume with concentration of
1500 ppm, 3000 ppm, 6000 ppm, and 10000 ppm hydrophobic nanosilica, correspondingly. It is worth
to mention that all the core flooding tests were carried out to determine the optimum concentration
of hydrophobic nanosilica. Secondary hydrophobic nanoflooding for 1500 ppm, 3000 ppm, 6000 ppm,
and 10000 ppm recovers 64.045%, 74.426%, 79.13%, and 80.234% OOIP, Respectively. Two main factors
were caused 10000 ppm of surfactant can improved recovery up to 80.234% of OOIP, first reason is lowering IFT between two immiscible phases (water and oil) and consequently formation of microemulsion
between oil and nanofluid and second reason is reduction of mobility ratio between oil and nanofluid
by rising the viscosity of water. Figure 3 shows ultimate recovery (%OOIP) as function of hydrophobic
nanosilica concentration.

4. Conclusions
The use of combination of hydrophobic nanosilica for EOR implication in a naturally fractured reservoir
was systematically investigated. The following deductions can be extracted based on outcomes from this
work:
• Hydrophilic nanosilica can improved oil recovery up to 80.234 for 10000 ppm of nanosilica in water
solution.
• Recovery efficiency of nanosilica gradually increased from 6000 ppm to 10000 ppm of nanosilica.
• The significant phenomenon that enhanced the oil recovery factor of nanosilica flooding is reducing
the interfacial tension between injection fluid and oil and then can create high viscosity micro emulsion. This process is EOR by mean of IFT reduction. However, increasing in viscosity of injected
fluid and then reduce of mobility ration between oil and injected fluid is a second phenomenon for
improvement of ultimate recovery and this method is EOR by mean of mobility control (mobility
reduction).


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M.-A. AHMADI ET AL.

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References
Ahmadi, M. A., and Shadizadeh, S. R. (2012). Adsorption of novel nonionic surfactant and particles mixture in carbonates:
enhanced oil recovery implication. Energy Fuels 26:4655–4663.
Ahmadi, M. A., and Shadizadeh, S. R. (2014). Nano fluid in hydrophilic state for EOR implication through carbonate
reservoir. J. Dispers. Sci. Technol. 35:1537–1542.
Di, Q., Shen, C., Wang, Z., Jing, B., Gu, C., and Qian, Y. (2010). Innovative drag reduction of flow in rock’s micro-channels
using nano particles adsorbing method. SPE 130994, CPS/SPE International Oil & Gas Conference and Exhibition,
Beijing, China, June 8–10.
Evdokimov, I. N., Eliseev, N. Y., Losev, A. P., and Novikov, M. A. (2009). Emerging petroleum-oriented nanotechnologies
for reservoir engineering. SPE 102060, SPE Russian Oil and Gas Technical Conference and Exhibition, Moscow, Russia,
October 3–6.
Ju, B., Dai, S., Jinggong, D., Luan, Z., Zhu, T., Su, X., and Qiu, X. (2002). A study of wettability and permeability change
caused by adsorption of nanometer structured polysilicon on the surface of porous media. SPE 77938, SPE Asia Pacific
Oil and Gas Conference and Exhibition, Melbourne, Australia, October 8–10.
Ju, B., and Fan, T. (2009). Experimental study and mathematical model of nanoparticle transport in porous media. Powder
Technol. 192:195–202.
Ju, B., Fan, T., and Ma, M. (2006). Enhanced oil recovery by flooding with hydrophilic nanoparticles. China Particuol.
4:41–46.
Kanj, M. Y., Funk, J. J., and Al-Yousif, Z. (2009). Nanofluid coreflood experiments in the ARAB-D. SPE 126161, SPE Saudi
Arabia Section Technical Symposium and Exhibition, AlKhobar, Saudi Arabia, May 9–11.
Rodriguez, R., Roberts, M., Yu, H., Huh, C., and Bryant, S. L. (2009). Enhanced migration of surface-treated nanoparticles
in sedimentary rocks. SPE 124418, SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, October
4–7.
Singh, S. K., Ahmed, R. M., and Growcock, F. (2010). Vital role of nanopolymers in drilling and stimulations fluid applications. SPE 130413, SPE Annual Technical Conference and Exhibition, Florence, Italy, September 19–22.
Skauge, T., Spildo, K., and Skauge, A. (2010). Nano-sized particles for EOR. SPE 129933, SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, April 24–28.
Xiangling, K., and Ohadi, M. (2010). Applications of micro and nano technologies in the oil and gas industry - overview
of the recent progress. SPE 138241, Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, United

Arab Emirates, November 1–4.
Yu, H., Kotsmar, C., Yoon, K. Y., Ingram, D. R., Johnston, K. P., Bryant, S. L., and Huh, C. (2010). Transport and retention of aqueous dispersions of paramagnetic nanoparticles in reservoir rocks. SPE 129887, SPE Improved Oil Recovery
Symposium, Tulsa, Oklahoma, April 24–28.