School of Earth, Energy and Environmental Sciences

Showing 651-660 of 663 Results

  • Wonjin Yun

    Wonjin Yun

    Postdoctoral Research Fellow, Energy Resources Engineering

    Current Research and Scholarly InterestsImproved understanding of the physicochemical mechanisms controlling the interplay between oil, water,and rock during EOR processes at pore scale is vital to achieve successful applications of enhanced oil recovery (EOR). Microfluidics provides an experimental platform to probe such interplay. The present work addresses greater realism in pore structure and visualization of micromodels for characterization of single and multiphase flows.

    We describe 4 advancements, as follows, and representative results. First, we demonstrate improved 3D structural realism of pores inside etched-silicon microfluidic devices. In particular, we etch the micropores 1.5 to 21 μm width) within a carbonate pore network less deeply than the wider macropores (>21 μm width). Second, we apply micro-particle image velocimetry (μ-PIV) to so-called end-point relative permeability measurements of oil and water as well as pore-scale observationsmduring imbibition and drainage processes. The μ-PIV technique provides insights into the fluid dynamics within microfluidic channels and relevant fluid velocities controlled predominantly by changes in pore width and depth. Third, we demonstrate that micromodels may be monitored using advanced spectral imaging that enables real-time and in-situ quantification of the local viscosity of shear-thinning and viscoelastic fluids. Spectral imaging of in situ viscosity paves the way for validation and optimization of computational fluid dynamics models for non-Newtonian viscoelastic EOR polymers. Fourth, we show the application of deep-learning to the micromodel images for the automated analysis of surface properties. Specifically, understanding wettability of porous media, namely the relative affinity of the fluids for the solid, and its influence on the efficiency of wetting-phase displacement of non-wetting phase is a key factor determining multiphase flow. Hence, we want to achieve a systematic methodology to study themlarger domain of porous media that consists of a tremendous number of complex interplays between surface and reservoir fluids at the pore and pore network scale. With proper training, deep-learning has a great potential to serve as a quick and comprehensive image classification and evaluation tool.

  • Howard Zebker

    Howard Zebker

    Professor of Electrical Engineering and of Geophysics

    Current Research and Scholarly InterestsResearch
    My students and I study the surfaces of Earth and planets using radar remote sensing methods. Our specialization is interferometric radar, or InSAR. InSAR is a technique to measure mm-scale surface deformation at fine resolution over wide areas, and much of our work follows from applying this technique to the study of earthquakes, volcanoes, and human-induced subsidence. We also address global environmental problems by tracking the movement of ice in the polar regions. whose ice mass balance affects sea level rise and global climate. We participate in NASA space missions such as Cassini, in which we now are examining the largest moon of Saturn, Titan, to try and deduce its composition and evolution. Our work includes experimental observation and modeling the measurements to best understand processes affecting the Earth and solar system. We use data acquired by spaceborne satellites and by large, ground-based radar telescopes to support our research.

    I teach courses related to remote sensing methods and applications, and how these methods can be used to study the world around us. At the undergraduate level, these include introductory remote sensing uses of the full electromagnetic spectrum to characterize Earth and planetary surfaces and atmospheres, and methods of digital image processing. I also teach a freshman and sophomore seminar course on natural hazards. At the graduate level, the courses are more specialized, including the math and physics of two-dimensional imaging systems, plus detailed ourses on imaging radar systems for geophysical applications.

    Professional Activities
    InSAR Review Board, NASA Jet Propulsion Laboratory (2006-present); editorial board, IEEE Proceedings (2005-present); NRC Earth Science and Applications from Space Panel on Solid Earth Hazards, Resources, and Dynamics (2005-present); Chair, Western North America InSAR (WInSAR) Consortium (2004-06); organizing committee, NASA/NSF/USGS InSAR working group; International Union of Radioscience (URSI) Board of Experts for Medal Evaluations (2004-05); National Astronomy and Ionospheric Center, Arecibo Observatory, Visiting Committee, (2002-04; chair, 2003-04); NASA Alaska SAR Facility users working group (2000-present); associate editor, IEEE Transactions on Geoscience and Remote Sensing (1998-present); fellow, IEEE (1998)