Kim, Mike

Geologic storage of carbon dioxide (CO2) into deep
saline aquifers is a promising strategy for mitigation
of global atmospheric CO2 levels-a main cause of
climate change. These aquifers have the capacity
to safely store significant amounts of CO2 and are
available worldwide. As such, reaction dynamics and
multiphase transport accompanying CO2 injection in
deep aquifers are important to understanding CO2
sequestration processes and therefore they have
been extensively studied. Despite the comprehensive
findings, there are still urgent needs for understanding
of interactions between injected CO2 and
resident fluids since these interactions could determine
the total CO2 storage rate and capacity. The
objective of this study is to investigate fundamental
physics of water evaporation at different salinities under the CO2-rich environment. Microfluidic techniques
visualize and quantify evaporation behavior
of water in real-time in a simple 1D microchannel
geometry. The detailed CO2-water interactions and
underlying physics will be discussed.

More than 1 trillion barrels of oil deposited worldwide
is heavy oil and natural bitumen. Due to their
high viscosity and high density, extraction efficiency
of heavy oil and bitumen from natural reservoirs
is known to be less than 5% with the conventional
primary recovery methods. To increase their recovery
efficiency, a technique, known as enhanced oil
recovery, has been developed using nanoparticles,
surfactant, dispersant, and polymers. Among these
materials, surfactants and dispersants lower interfacial
tension between oil and the resident fluid; therefore
enhance mobilization of oil. The objective of this
project is to further improve the recovery efficiency
of heavy oil by a combined effect of surfactant and
dispersant. When the mixture of surfactant and dispersant
in an aqueous solution is injected to oil-rich
porous media, microfluidic visualization techniques
will be employed to investigate the overall recovery
rate. The possibility and effectiveness of the proposed idea will be discussed.

Aqueous microdroplets have shown great potential
in various applications such as material synthesis,
chemical reactions, and drug discovery. The
objective of this research is to generate aqueous
microdroplets in water using microfluidic techniques.
Compared to conventional aqueous droplets in an oil
phase, droplets generated from the proposed system
will be more biocompatible and simply manufactured.
To achieve this goal, the research focuses on
understanding fundamental physics behind droplet
generation at various geometries and input conditions.
This understanding can subsequently help us
obtain microdroplets with targeted properties. Several
microdroplet generators made of polydimethylsiloxane
(PDMS) transparent polymer are fabricated
and an aqueous two-phase system (ATPS) made up
of two water-based polymers, polyethylene glycol
(PEG) and dextran (DEX) is used in these generators.
The results successfully demonstrate that the
proposed droplet generators produce aqueous microdroplets
at various sizes at different frequencies.
The controllability and tunability of the properties of
microdroplets will be discussed.