1. Research Institute of Petroleum Industry
Faculty of Research and Development of Oil Upstream Industry
Petroleum Engineering Department
Tehran, Iran
Monitoring Wettability Alteration of Porous Media by Silica Nanoparticles: An Experimental Approach
by: Saber Mohammadi
November 2015

2. Outlines Introduction 1 Approach & Organization 2
Results & Discussions 3
Concluding Remarks 4

3. Nanotechnology & Solution to Upstream Oil Industry Challenges
Introduction
Exploration
IOR/EOR
Production
Drilling
Reservoir Management
Nanotechnology & Solution to Upstream Oil Industry Challenges

4. Introduction Motivation:
Increasing of world demand for energy requires the increase in production of crude oil through different EOR scenarios.
The feasibility of these scenarios depends on many factors such as flow mechanisms in porous media and properties of porous medium at microscopic/macroscopic levels.
An important part of these methods is related to the wettability of the reservoir rock.
Understanding the porous media wettability is crucial for well planning and optimizing EOR scenarios.
Wettability alteration is one of the most important methods for oil recovery from sandstone and carbonated reservoirs.
Despite the extensive literature about the effect of wettability on microscopic displacements of fluid flow, pore-scale visualization of the role of “silica nanoparticles” on wettability of the reservoir rock has not been well addressed.

5. Wettability Alteration Methods
Introduction
Wettability Alteration Methods
Thermal Methods
hot water
steam injection
Chemical Methods
surfactant
nano materials

6. Introduction Nanotechnology & Wettability Alteration:
The use of nanotechnology has recently gained momentum in the oil and gas industry for its potential applications in EOR processes.
In recent years, attention has been drawn to the effect of nanoparticles on the wetting behavior of reservoir rocks.
Wettability alteration by nanoparticles is due to their adsorption on rock surface and forming a water-wet layer on it; thus the viscous forces required to overcome capillary forces are reduced dramatically.
Illustration of wedge-film at the base of the drop due to disjoining pressure
(Wasan et al., 2011)

7. Introduction
Characteristics and Properties of Silica Nanoparticles (SNPs) :
SNPs are water-soluble, non-toxic, odorless particles that can easily be fabricated and modified at low cost.
SNPs are characterized by their very low bulk density, about 0,04 – 0,1 g/cm3, and a high specific surface area, typically 200 – 300 m2/g.
SNPs can move freely through the porous media due to the small size of nanoparticles.
SNPs have high surface area which lead to an increased tendency of silica nanoparticles to adsorb on the walls of porous media.
SNPs have high heat transfer efficiency.

8. Approach & Organization
Goal:
assess the effect of hydrophilic silica nanoparticles (SNPs) on wettability of reservoir rock and pore-scale water flooding in one quarter 5-spot glass micro-models at different temperatures and concentration of nanoparticles
Methodology:
Contact angle measurement were conducted to see how SNPs affect fluid interfaces at a solid surface (oil-water-rock system)
Flooding experiments in 5-spot glass micro-models with water flooding & dispersed silica nanoparticles in water (DSNPW)

9. Approach & Organization
Experimental Setup: contact angle measurement
contact angle measurement in sessile drop method

10. Approach & Organization
Experimental Setup: micro-model apparatus
Schematic diagram of the micro-model setup (Mohammadi et al., 2013a)
Picture showing the main components of the micro-model setup

11. Approach & Organization
Why micro-model experiments?
Effective and relatively inexpensive tools for visualizing and quantifying complex flow phenomena through the porous media.
Fluid displacement and redistribution as well as alteration of wettability can be viewed and monitored.
Ability to visualize the fluid dynamics.
Utilizing different porous media.
Better understanding of displacement processes at pore level.
Smaller sample volume in comparison to the core flood experiments.

12. Approach & Organization
Properties of silica nanoparticles
TEM image of dispersed silica nanoparticles in water (DSNPW)

13. Approach & Organization
Physical and hydraulic properties of the constructed micro-model
Injection Port
Production Port
schematic of laser-based flow pattern used for flooding experiments (Mohammadi et al., 2013b)

14. Approach & Organization

15. Results & Discussions: Contact Angle Measurement
Changes in the contact angle of carbonated rock slice aged in heavy crude oil vs. time at 25 oC and 80 oC

16. Results & Discussions: Contact Angle Measurement
Slices of carbonated rock used in this study
SEM image of an oil-wet carbonated rock slice before aging in 0.10 %wt DSNPW
SEM image of an oil-wet carbonated rock slice after aging in 0.10 %wt DSNPW

17. Results & Discussions: Contact Angle Measurement
T=25 oC
T=80 oC
Effect of SNP concentrations on contact angle of carbonated rock slices vs. time

18. Results & Discussions: Contact Angle Measurement
Effect of SNP concentrations on contact angle of carbonated rock slices vs. temperature

19. Results & Discussions: Flooding Experiments
Visualization of oil displacement during water flooding

20. Results & Discussions: Flooding Experiments
Visualization of oil displacement during DSNPW (0.5%wt) flooding

21. Results & Discussions: Flooding Experiments
Oil recovery factor vs. pore volume of injected fluids
Injected fluid breakthrough time vs. SNP concentrations

22. Results & Discussions: Flooding Experimentsa) b)
Pore-scale visualization of media wettability during flooding experiments: a) water flooding, b) DSNPW flooding

23. Results & Discussions: Flooding Experiments
Simple schematic of a sample throat representing permeability reduction due to silica adsorption
Permeability of porous media during DSNPW flooding with different weight percent of SNPs

24. Concluding Remarks
This work illustrates the successful application of SNPs for wettability alteration.
The hydrophilic nature of selected SNPs, strong hydrogen bonding between silica and water and therefore increment in surface free energy are responsible for wettability alteration from oil-wet to water-wet.
Contact angle measurement on slices of carbonated rock showed that changes of contact angle is more intensified by SNPs concentration and temperature.
DSNPW flooding in 5-spot glass micro-models results in higher ultimate oil recovery as well as better sweep efficiency in comparison to the water flooding.
Increasing the SNPs concentration postpones the breakthrough of injected fluid during flooding experiments in 5-spot glass micro-models.
DSNPW flooding in f5-spot glass micro-models results in higher ultimate oil recovery as well as better sweep efficiency in comparison to the water flooding.

25. Concluding Remarks
The distribution of DSNPW solution during flooding tests in pores and throats showed strong water-wet condition after flooding with high concentration of nanosolution.
Due to adsorption of SNPs on the glass surface in pores and throats, the wettability alteration by chemical treatment led to an absolute permeability reduction.
Results of this work suggest the SNPs as an additive to water for improvement of oil recovery during water flooding instead/before implementation of other suitable EOR schemes.

26. Selected References
Mohammadi, S., Ghazanfari, M. H., Masihi, M. “A pore-level screening study on miscible/immiscible displacements in heterogeneous models”. Journal of Petroleum Science and Engineering. 2013a, 110,
Mohammadi, S., Maghzi, A., Ghazanfari, M. H., Masihi, M., Mohebbi, A., Kharrat, R. “On the control of glass micromodel characteristics developed by laser technology”. Energy sources, Part A: recovery, utilization, and environmental effects. 2013b, 35(3),
Wasan, D., Nikolov, A., Kondiparty, K. "The wetting and spreading of nanofluids on solids: Role of the structural disjoining pressure." Current Opinion in Colloid & Interface Science. 2011, 16 (4),

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Your thorough Attention