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Use of Silica and Iron-Oxide Nanoparticles with Specific

Surface Coatings for Enhanced Oil Recovery

Chun Huh Dept. of Petroleum & Geosystems Engineering

University of Texas at Austin

IOR Norway 2015: “Joining Forces to Recover More”

March 28-29, 2015

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•  Introduction -- Requirements for Nanoparticles for Subsurface Applications •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control” •  Magnetic NPs for Removal of “Contaminants” from

Water •  Conclusions

Agenda

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Basic Requirements for Nanoparticles

•  (1) Long-term dispersion stability in reservoir fluids (2) Able to transport long distance in the reservoir (3) Able to attach preferentially at target sites

•  NP surface coating should not desorb in reservoir brine; coating needs to be covalently bonded to NP surface, or wrap around NP as a non-detachable polymeric film

•  Reservoir brine salinity and pH are important design parameters for optimum surface coating

Scheme  of  Crosslinking  onto  Nanopar5cles  

Nanoparticle-Stabilized Foams and Emulsions: Basic Mechanism

•  If CO2 (or oil) and water partially wet particle surface, nanoparticle acts like surfactant, forming “Pickering emulsion/foam”

•  Hydrophilic NP (θ < 90°) forms CO2-in-water foam; Hydrophobic NP (θ > 90°) forms water-in-CO2 foam

•  NPs, being solid, provide better tolerance to high-T and high-salinity than surfactants; and can carry other functionalities

θ θ water

CO2

CO2

water

CO2

water

Si(CH3)2Cl2 (76% SiOH) Fluorosilanes

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Synthesis & Surface Coating Iron-oxide paramagnetic NP clusters

• Synthesis -  Co-precipitation of iron-chloride salts in alkaline media → Fe3O4

• Surface coating ü  The requirements for stability and transportability can

be accomplished with optimization of generally hydrophilic coating

ü  To achieve the targeted delivery, polymers with 2-3 ligands are usually needed

(Ligand for attachment to NP surface; hydrophilic ligand; hydrophobic ligand)

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•  Introduction •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control” •  Magnetic NPs for Removal of “Contaminants” from

Water •  Conclusions

Agenda

Nanoparticle-stabilized foam: Smart alternative in CO2 mobility control

Alternatives in CO2 mobility control • Direct CO2 thickening • CO2/Brine surfactant-stabilized foam • Nanoparticle-stabilized CO2 foam

Why nanoparticles? • Potentially improve long-term stability

•  Tolerant to harsh subsurface environment, such as high salinity, hardness, and temperature

•  Low adsorption on reservoir rock

• Threshold shear rate raises possibility of ‘smart fluid’

• Nanoparticle core can carry other functionalities (Magnetic/Catalytic/Conductive)

Nanoparticle-Stabilized CO2 Foams: Apparent Viscosity

Shear Rate = 1300 Sec-1 and Temperature = 22 °C

No Foam

Foam

Typical Foam Coreflood Result in Sandstone

Slide  9  

0  

5  

10  

15  

20  

25  

30  

0   1   2   3   4   5   6   7   8  

Core  pressure  do

rp  (P

sig)  

PV  

3 ml/min 6 ml/min 9 ml/min 12 ml/min

baseline (water + CO2)

with nanoparticles

Particle: 1 wt% 5nm PEG (3M) in DI water

Pressure: 2000 psia Temperature: 23 degC (room) CO2:NP: 2:1 Matrix type: Boise Sandstone

(1600 mD)

MR F = 1

MR F = 1:7

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•  Introduction •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control” •  Magnetic NPs for Removal of “Contaminants” from

Water •  Conclusions

Agenda

Improved mobility control for heavy oil displacement o  With its high apparent viscosity, emulsions can improve sweep efficiency o  By carrying light HC as internal phase, emulsions can help reduce

viscosity of heavy oil

Nanoparticle-Stabilized Emulsions for EOR

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•  Introduction •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control” •  Magnetic NPs for Removal of “Contaminants” from

Water •  Conclusions

Agenda

Useful Properties of Paramagnetic Nanoparticles

•  By applying magnetic field gradient, NPs can be forced to move in desired direction

•  Under applied high-frequency magnetic oscillation, NPs generate intense, localized heat

•  Under applied field, NP ensemble generates magnetic induction field

•  Can be designed to attach to desired interfaces, for stable emulsion generation or for targeted delivery

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•  Introduction •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control”

-- MNP-based hyperthermia heating to form gel blockage at selected locations, using temperature-responsive polymer •  Magnetic NPs for Removal of “Contaminants” from

Water •  Conclusions

Agenda

Proposed “Conformance control method” §  Injection of a small bank of (gelant

polymer + crosslinker + paramagnetic nanoparticles) into well.

-- The mixture goes into all layers, but more into the high-k layers

§  Magnetic logging is run vertically, to detect the zones with more NPs (= high-k layers).

§  Magnetic field generator is lowered into wellbore to apply magnetic oscillation only to the high-k layers. Polymer gel is formed with rapid, localized heating.

§  Un-gelled polymers in the low-k layers are produced back.

§  If gel removal is desired, sustained heating will locally burn the gel.

magnetic sensor

high-k layer

low-k layer

magnetic heater

gel

un-gel

un-gelled soln

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Paramagnetic NP Heating E&P Applications •  High-frequency paramagnetic NP heating is analogous to microwave

heating: Rapid magnetic spin in single-domain NPs generates intense heat. The “hyperthermia” heating is highly localized and controllable.

ΔThydrophilic ~ 70ºK in 10 secs (10wt% NP in water) ΔThydrophobic ~ 40ºK in 30 secs (10.5wt% NP hexane)

Fe3O4 NP-based Magnetic Heating for Formation of HPAM-PEI Gel

2000ppm HPAM + 1wt% PEI + 0.23wt% Fe3O4-NP

Magnetic power 2 KW - 725 KHz 21A current

PEI HPAM-PEI gel

HPAM

Heat

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•  Introduction •  Silica NP-Stabilized CO2 Foams for Mobility Control •  Silica NP-Stabilized Emulsions for Heavy Oil

Recovery •  Magnetic NPs for “Precision Conformance Control” •  Magnetic NPs for Removal of “Contaminants” from

Water -- Attachment of MNPs to crude oil droplets (or other target chemicals);

and their separation by magnetic field -- Selective adsorption of divalent cations on MNPs; and their separation by magnetic field •  Conclusions

Agenda

Schematics of the process for oil droplet separation and recycling of MNPs

Oil droplet separation

MNPs regeneration

Emulsion

Magnet

Collect

Separate

Mix (1:1 vol)

Separated clean water

Wash oil droplet attached MNPs to desorb oil droplets

MNP

Re-disperse and reuse

Magnet

: Oil droplet

Separation of oil droplets by MNP attachment and magnetic force application

Attachment of MNP on oil droplet

oil

Separation of MNP attached oil droplets

oil

Buoyancy force (Fb)

Drag force (Fd)

Gravitational force (Fg)

Where, Vp = volume of particle Χp and Χf = volume magnetic susceptibility of particle and fluid B = external magnetic field

Images of 0.25 wt.% of TAN 2.9 oil droplet separation in different MNP concentrations

Fe = 1500 mg/L Fe = 750 mg/L Fe = 600 mg/L

Fe = 500 mg/L Fe = 300 mg/L Fe = 130 mg/L

MNPs were stuck on a wall that were not collected by a magnet

Oil droplet removals using regenerated A-MNP 0.25 wt.% oil content: 13000 mg/L of Fe

Schematic of the Multivalent Cation Removal

Magnetic field

: Cations

Fe3O4

Mix and adsorb Re-suspend Fe3O4

Cation removal Fe3O4 regeneration

Softened water

Fe3O4 re-use

Magnetic field

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Conclusions

•  Adaptation of the huge advances made by other industries on the nanotechnology applications is rapidly gaining momentum in the upstream oil industry, with potential of huge business impacts.

•  Nanoparticles with a special surface coating tailored to achieve certain desired functionalities (targeted delivery, sensing, “intelligent” mobility control, etc.) have great potential for various reservoir applications.

•  Nanoparticle-stabilized emulsions and foams show good promise as conformance- and mobility-control agents for EOR; and as “intelligent” additives for drilling fluids and completions cement.

•  Paramagnetic nanoparticles have unique properties that could be utilized for many E&P applications: (1) intense localized heating; (2) controllable movement; (3) magnetic pressure generation; and (4) induction field generation for sensing.