Use of Silica and Iron-Oxide Nanoparticles with Specific Surface Coatings for Enhanced Oil Recovery

Texas 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

Texas Agenda Introduction -- Requirements for Nanoparticles for Subsurface Applications Silica NP-Stabilized CO 2 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

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 Texas

Nanoparticle-Stabilized Foams and Emulsions: Basic Mechanism If CO 2 (or oil) and water partially wet particle surface, nanoparticle acts like surfactant, forming Pickering emulsion/foam Hydrophilic NP (θ < 90 ) forms CO 2 -in-water foam; Hydrophobic NP (θ > 90 ) forms water-in-co 2 foam NPs, being solid, provide better tolerance to high-t and high-salinity than surfactants; and can carry other functionalities θ CO 2 water CO 2 water θ CO 2 water Si(CH 3 ) 2 Cl 2 (76% SiOH) Fluorosilanes

Synthesis & Surface Coating Iron-oxide paramagnetic NP clusters Synthesis - Co-precipitation of iron-chloride salts in alkaline media Fe 3 O 4 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 Texas (Ligand for attachment to NP surface; hydrophilic ligand; hydrophobic ligand)

Nanoparticle-stabilized foam: Smart alternative in CO 2 mobility control Alternatives in CO 2 mobility control Direct CO 2 thickening CO 2 /Brine surfactant-stabilized foam Nanoparticle-stabilized CO 2 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 CO 2 Foams: Apparent Viscosity No Foam Foam Shear Rate = 1300 Sec -1 and Temperature = 22 C

Slide 9 Typical Foam Coreflood Result in Sandstone Core pressure dorp (Psig) 30 25 20 15 10 5 0 3 ml/min 6 ml/min 9 ml/min 12 ml/min M R F = 1 with nanoparticles baseline (water + CO 2 ) M R F = 1:7 0 1 2 3 4 5 6 7 8 PV 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)

Nanoparticle-Stabilized Emulsions for EOR 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

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

Texas Agenda Introduction Silica NP-Stabilized CO 2 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

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 (= highk 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. magnetic sensor high-k layer low-k layer un-gelled soln magnetic heater gel If gel removal is desired, sustained heating will locally burn the gel. un-gel

Texas 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. ΔT hydrophilic ~ 70ºK in 10 secs (10wt% NP in water) ΔT hydrophobic ~ 40ºK in 30 secs (10.5wt% NP hexane)

Fe 3 O 4 NP-based Magnetic Heating for Formation of HPAM-PEI Gel HPAM PEI Heat HPAM-PEI gel Magnetic power 2 KW - 725 KHz 21A current 2000ppm HPAM + 1wt% PEI + 0.23wt% Fe 3 O 4 -NP

Agenda Introduction Silica NP-Stabilized CO 2 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 Texas

Schematics of the process for oil droplet separation and recycling of MNPs Oil droplet separation Emulsion Separated clean water Separate Mix (1:1 vol) Collect Magnet MNPs regeneration : Oil droplet Wash oil droplet attached MNPs to desorb oil droplets Magnet MNP Re-disperse and reuse

Separation of oil droplets by MNP attachment and magnetic force application Attachment of MNP on oil droplet Separation of MNP attached oil droplets Buoyancy force (F b ) oil Drag force (F d ) oil Gravitational force (F g ) Where, V p = volume of particle Χ p and Χ f = 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 MNPs were stuck on a wall that were not collected by a magnet Fe = 500 mg/l Fe = 300 mg/l Fe = 130 mg/l

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

Schematic of the Multivalent Cation Removal Cation removal : Cations Fe 3 O 4 regeneration Fe 3 O 4 Softened water Mix and adsorb Magnetic field Re-suspend Fe 3 O 4 Magnetic field Fe 3 O 4 re-use

Texas 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.