Event Category: Friday Informal Seminar Hour (FISH)

Dr. Christopher Leonardi, Associate Professor at the University of Queensland, presents this week’s Friday Informal Seminar Hour: “Migration, Segregation, Percolation, and Clogging: Recent Learnings from High-Fidelity Simulations of Proppant Transport”.

Abstract: The transport of multiphase suspensions in confined geometries is relevant in a diverse range of flows in science and engineering, from drug transport in the bloodstream, to cell separation in microfluidic devices, and proppant transport in fractured gas and geothermal reservoirs. In this talk, a computational framework for the resolved simulation of such suspensions is presented, using the fully coupled lattice Boltzmann and discrete element methods (LBM-DEM) as its basis. Application to industrially relevant problems highlight new and interesting phenomena, including reverse migration of select species in polydisperse suspensions, the profound influence of electrostatics on clogging and jamming in narrow channels, and the potential for flow reversal to break down some of these behaviours.

About the speaker: Christopher Leonardi is an Associate Professor within the School of Mechanical and Mining Engineering at The University of Queensland (Australia) and currently a Visiting Professor at City College New York (CCNY). He completed his PhD in computational mechanics at The University of Wales (UK) and his BE (Honours Class I) in mechanical engineering at James Cook University (Australia). Prior to joining UQ, Christopher spent three years as a postdoctoral research fellow in the Department of Civil and Environmental Engineering at the Massachusetts Institute of Technology.

Associate Professor Leonardi’s research is focused on the development and application of computational models of complex fluid-solid interactions, including suspension transport, porous media flow, multiphase flows, and poromechanics. The outputs of his work are applied to provide insight into the complex characteristics of subsurface fluid and solid mechanics in gas production from unconventional reservoirs (e.g. coal seams) and microfluidic devices (e.g. cell separators). Current and recent projects include studies on hydraulic fracturing and proppant transport in coal seam gas (CSG) reservoirs, two-phase flow in rock fractures, and oscillatory suspension transport. Christopher and his group of postdoctoral researchers and postgraduate students possess expertise in a range of computational techniques, including the lattice Boltzmann, discrete element, finite element, and finite difference methods. His team collaborates closely with national computing facilities, such as Pawsey Supercomputing Centre, to development, implement, and apply these techniques to large-scale engineering problems.

Zoom link: https://mit.zoom.us/j/95374035027?pwd=Yulw92aNfHOiDPp27WKQL4bgba3iew.1

Prof. Ruben Juanes, a longtime ERL principal investigator and faculty-member in both EAPS and CEE, presents “Fluids, Fingers, Fractures and Fractals: Patterns in Porous Media” as part of the ERL Friday Informal Seminar Hour.

Abstract: The displacement of one fluid by another in a porous medium gives rise to a rich variety of hydrodynamic instabilities. Beyond their scientific value as fascinating models of pattern formation, unstable porous-media flows are essential to understanding many natural and man-made processes, including water infiltration in the vadose zone, carbon dioxide injection and storage in deep saline aquifers, methane venting from organic-rich sediments, and fracturing from fluid injection. Here, we review a handful of these hydromechanical instabilities, elucidate the key physics at play, and point to modeling frameworks that permit quantitative assessments of their impact at the geologic scale.

About the speaker: Ruben Juanes is professor in Civil and Environmental Engineering, and Earth, Atmospheric and Planetary Sciences at MIT, where he has been since 2006. He is an expert in fluid flow through porous media and in geomechanics, and has applied his research to the fields of energy resources, carbon capture and storage, gas hydrates, water infiltration and soil irrigation, and induced seismicity. He holds an undergraduate degree from University of A Coruña (Spain) and graduate degrees from UC Berkeley, all in Civil and Environmental Engineering. He is a fellow of the American Geophysical Union and the American Physical Society.

Zoom link

Prof. Admir Masic of MIT Civil & Environmental Engineering presents “On the Multifunctional Future of Concrete​” as part of the ERL Friday Informal Seminar Series.

Abstract: Concrete is the most widely used construction material, and the carbon-intensive production of cement- its key ingredient – accounts for nearly 8% of global CO₂ emissions. To meet the urgent need for decarbonization, we must rethink concrete’s role in the built environment. In this talk, we will explore how novel cement chemistries and advanced analytical techniques – particularly Raman spectroscopy – are enabling the development of multifunctional concretes. From CO₂-sequestering formulations to Roman-inspired self-healing cements and electrically conductive energy-storing systems, these innovations position concrete not just as a structural material but as a carbon sink and functional infrastructure component for a sustainable future.

Zoom link: https://mit.zoom.us/j/95374035027?pwd=Yulw92aNfHOiDPp27WKQL4bgba3iew.1

FISH talks are open to the public but building 54 now requires an MIT ID to enter during the day. If you would like to attend in person but do not have an MIT ID, please contact us at erl-info@mit.edu.

Simple estimates of space & time variation of mineral dissolution & precipitation around boreholes injecting CO2-rich aqueous fluid for storage: Clogging, or not? (and some CCS politics, why not?)

FISH talks are open to the public but building 54 currently requires an MIT ID to enter. If you would like to attend in person but do not have an MIT ID, please contact erl-info@mit.edu.

Abstract: A long-standing concern for subsurface CO2 storage in reactive rock formations (ultramafic rocks including mantle peridotite, basaltic lavas) has been the potential for clogging of pore space with newly formed carbonate minerals. We have used EQ3/6 geochemical models and simple geometric parameterizations to explore length and time scales for precipitation and dissolution zones around boreholes used to inject CO2-rich, aqueous fluids for geologic storage via carbon mineralization.

We first consider equilibrium reactions in uniform, cylindrical rings around a borehole. Initially, and far from the borehole, fluid-rock mass ratios are low, and fluid is close to equilibrium with the rock. As fluid-rock ratios reach intermediate values (5-10), precipitation of carbonate minerals, plus some hydration and oxidation, lead to increasing solid mass and volume, potentially filling pore space, even in basalt flow tops and other permeable horizons with initial porosity ~10 vol%. Where fluid-rock ratios rise to high values (>10), dissolution of carbonates and silicates in low pH CO2-rich fluids moves the precipitation zone outward, and creates new pore space. For a given injection rate, we estimate the radii of precipitation and dissolution zones around the borehole as a function of time. Porosity changes are smaller when the initial rock is highly altered, minimizing solid volume increase due to hydration and oxidation, but mineralization still increases solid volume by > 10 vol%.

Using very simple parameterizations, we then show how kinetic inhibition – of mineral precipitation and/or reactions changing pH – yields precipitation zones with larger volumes, extending farther from the borehole at any given time. Mineral formation in these wider precipitation zones is diffusely distributed, and may never fill pore space.

Moreover, the “reaction infiltration instability” can create porous dissolution channels with high fluid-rock ratios, focusing flow of acidic, CO2-rich fluids farther from the borehole, penetrating cylindrical “precipitation fronts”. This could distribute precipitation over a larger rock volume and avoid clogging of pore space. Indeed, in this application, the reaction infiltration instability could be tuned, to form holes through precipitation fronts, accessing additional pore volumes, and optimizing carbon mineralization throughout a target aquifer, in both sedimentary and igneous rocks.