January 2023: “Green” Use of Nanoparticles and Nanobubbles in the Oil Industry

Abstract

Nano-dispersions (solid particles, liquid droplets, and gas bubbles whose size is smaller than 100 nm) can flow freely in porous media and have very large surface area per mass so that their surfaces can serve as effective substrates for reactive, catalytic, sensing and other functions deep in the reservoir. Their “green” use in oilfields is highlighted with some examples from UT Petroleum & Geosystems Engineering’s earlier and current research.

When synthesized with a surface coating tailored to achieve certain desired functionalities, nanoparticles provide unique and important benefits for a wide variety of oilfield applications. One example is the use of silica nanoparticles as foam/emulsion stabilizers, which offer an alternative option to surfactants when the reservoir temperature and/or salinity/hardness are high so that surfactants are not as effective. Ultra-dry but stable CO2-in-water foams can be generated with silica nanoparticles, which can be employed as a “waterless” fracturing fluid for unconventional reservoir development. Iron-oxide paramagnetic nanoparticles are widely employed in medical and other disciplines because they can be detected remotely; can be moved in a desired direction and collected under a magnetic field gradient; and can generate intense, highly localized heat with application of magnetic oscillation. One example oilfield application is the removal of microscopic crude oil droplets from produced water (which are difficult to remove by gravity settling). With a design surface coating on nanoparticles, the target “contaminants” are first attached to the particles, and then collected and removed by magnetic separation. Exciting feature of such “green” use of nanoparticles is that they can be regenerated and used again.

The recent remarkable findings that gas bubbles of nano size can remain stable in water for months, without use of surfactant or nanoparticle as a stabilizer, are bringing explosive applications development activities in agriculture, waste water treatment, and other industries. Such aqueous nanobubble dispersion (i) can contain a very large mass of gas (several ten times the thermodynamic solubility of gas) while effectively homogeneous and transparent; (ii) flows like water in porous media, unlike the bigger-size gas bubbles and foams whose trapping in rock is a big problem in the upstream oil industry; and (iii) has a high supersaturation of gas in water which can significantly enhance the geochemical reactions with reservoir rock and fluids. Such nanobubble dispersion can deliver a large mass of specific gases to a target subsurface formation with proper mobility control, for both improved oil recovery from, and CO2 sequestration in, mature hydrocarbon reservoirs and aquifer zones.

Bio

Chun Huh received his BS from Seoul National University in Korea and PhD from University of Minnesota (both in chemical engineering). Before joining the UT-Austin as a Research Professor, he worked as an Engineering Advisor at ExxonMobil Upstream Research Company in Houston, Texas for 27 years. He is one of the leading experts on surfactant- and polymer-based improved oil recovery (IOR) processes. “Chun Huh equation”, which predicts ultralow interfacial tension from microemulsion solubilization, is widely used for the design of surfactant-based IOR processes. At UT-Austin, he carried out research on use of nanoparticles for upstream oil industry applications, co-authoring over 60 publications on the subject and a book, “Practical Nanotechnology for Petroleum Engineers”. Prof. Huh is a recipient of the Society of Petroleum Engineers’ IOR Pioneer Award and a member of the U.S. National Academy of Engineering

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