A coreflood investigation of nanofluid enhanced oil recovery

Review of the litterature available outside the petroleum industry concerning wettability. This litterature discusses surface forces and their effects on wettability, including van der Waal and electrostatic forces. Hydrogen bonding and ion/water interactions, are also discussed. Advancing and receding contact angles for oil/water/mineral systems in terms of these surface forces are described.

Wettability : fundamentals and surface forces

The injected fluids in secondary processes supplement the natural energy present in the reservoir to displace oil. The recovery efficiency mainly depends on the mechanism of pressure maintenance. However, the injected fluids in tertiary or enhanced oil recovery (EOR) processes interact with the reservoir rock/oil system. Thus, EOR techniques are receiving substantial attention worldwide as the available oil resources are declining. However, some challenges, such as low sweep efficiency, high costs and potential formation damage, still hinder the further application of these EOR technologies. Current studies on nanoparticles are seen as potential solutions to most of the challenges associated with these traditional EOR techniques. This paper provides an overview of the latest studies about the use of nanoparticles to enhance oil recovery and paves the way for researchers who are interested in the integration of these progresses. The first part of this paper addresses studies about the major EOR mechanisms of nanoparticles used in the forms of nanofluids, nanoemulsions and nanocatalysts, including disjoining pressure, viscosity increase of injection fluids, preventing asphaltene precipitation, wettability alteration and interfacial tension reduction. This part is followed by a review of the most important research regarding various novel nano-assisted EOR methods where nanoparticles are used to target various existing thermal, chemical and gas methods. Finally, this review identifies the challenges and opportunities for future study regarding application of nanoparticles in EOR processes.

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Application of Nanoparticles in Enhanced Oil Recovery: A Critical Review of Recent Progress

This paper presents the results of imbibition tests using a reservoir crude oil and a reservoir brine solution with a high salinity and a suitable nanofluid that displaces crude oil from Berea sandstone (water-wet) and single-glass capillaries. The Illinois Institute of Technology (IIT) nanofluid is specially formulated to survive in a high-salinity environment and is found to result in an efficiency of 50% for Berea sandstone, compared to 17% using the brine alone at a reservoir temperature of 55 °C. We also present a direct visual evidence of the underlying mechanism based on the structural disjoining pressure for the crude oil displacement using IIT nanofluid from the solid substrate in high-salinity brine. These results aid our understanding of the role of the nanofluid in displacing crude oil from the rock, especially in a high-salinity environment containing Ca2+ and Mg2+ ions. Results are also reported using Berea sandstone and a nanofluid containing silica nanoparticles.

Enhanced Oil Recovery (EOR) Using Nanoparticle Dispersions: Underlying Mechanism and Imbibition Experiments

Wettability alteration of oil-wet carbonate by silica nanofluid.

The wetting and spreading behavior of pure liquids over solid surfaces changes if liquids contain nanosized spherical particles or surfactant micelles, globular proteins and macromolecules. Recent studies on the spreading of nanofluids have demonstrated the inadequacy of well-known concepts of the spreading and adhesion of pure liquids on solid surfaces in understanding nanofluid spreading behavior. This paper reviews the progress made in the wetting and spreading of nanofluids over solid surfaces with an emphasis on the complex interactions between the particles in the nanofluid and with the solid substrate, as well as the spreading of thin nanofluid films containing nanoparticles on hydrophilic surfaces driven by the structural disjoining pressure gradient. The spreading droplet advances as a series of distinct nanoparticle layers.

The wetting and spreading of nanofluids on solids: Role of the structural disjoining pressure

The wetting and spreading of nanofluids composed of liquid suspensions of nanoparticles have significant technological applications. Recent studies have revealed that, compared to the spreading of base liquids without nanoparticles, the spreading of wetting nanofluids on solid surfaces is enhanced by the structural disjoining pressure. Here, we present our experimental observations and the results of the statics analysis based on the augmented Laplace equation (which takes into account the contribution of the structural disjoining pressure) on the effects of the nanoparticle concentration, nanoparticle size, contact angle, and drop size (i.e., the capillary and hydrostatic pressure); we examined the effects on the displacement of the drop-meniscus profile and spontaneous spreading of a nanofluid as a film on a solid surface. Our analyses indicate that a suitable combination of the nanoparticle concentration, nanoparticle size, contact angle, and capillary pressure can result not only in the displacement of the three-phase contact line but also in the spontaneous spreading of the nanofluid as a film on a solid surface. We show here, for the first time, that the complete wetting and spontaneous spreading of the nanofluid as a film driven by the structural disjoining pressure gradient (arising due to the nanoparticle ordering in the confined wedge film) is possible by decreasing the nanoparticle size and the interfacial tension, even at a nonzero equilibrium contact angle. Experiments were conducted on the spreading of a nanofluid composed of 5, 10, 12.5, and 20 vol % silica suspensions of 20 nm (geometric diameter) particles. A drop of canola oil was placed underneath the glass surface surrounded by the nanofluid, and the spreading of the nanofluid was monitored using an advanced optical technique. The effect of an electrolyte, such as sodium chloride, on the nanofluid spreading phenomena was also explored. On the basis of the experimental results, we can conclude that a nanofluid with an effective particle size (including the electrical double layer) of about 40 nm, a low equilibrium contact angle ( 30 vol %) is desirable for the dynamic spreading of a nanofluid system with an interfacial tension of 0.5 mN/m. Our experimental observations also validate the major predications of our theoretical analysis.

Wetting and spreading of nanofluids on solid surfaces driven by the structural disjoining pressure: statics analysis and experiments.

Liquids containing nanoparticles (nanofluids) exhibit different spreading or thinning behaviors on solids than liquids without nanoparticles. Previous experiments and theoretical investigations hav...

Kirti Kondiparty

Papers

The wetting and spreading of nanofluids on solids: Role of the structural disjoining pressure

Wetting and spreading of nanofluids on solid surfaces driven by the structural disjoining pressure: statics analysis and experiments.

Nanoparticle Self-Structuring in a Nanofluid Film Spreading on a Solid Surface