Kevin M. Rosso, Ph.D.
Lab Fellow, Chemist; CUSSP Director Physical Sciences
Pacific Northwest National Laboratory
Abstract: The global imperative to develop and rely on clean sources of energy puts our mastery of the Earth’s deep subsurface into focus. Whether for accessing the mantle’s glow for bountiful geothermal heat or for safe disposal of hazardous wastes, humankind is now venturing more ambitiously deep underground where we are blinder than seeing into the far reaches of outer space. This talk will highlight how a multidisciplinary team is tackling a piece of this subsurface science challenge through the Center for Understanding Subsurface Signals and Permeability (CUSSP), a DOE Office of Science Energy Earthshot Research Center focused on enabling broad deployment of Enhanced Geothermal Systems (EGS).
The EGS goal of maintaining heat production for decades from the flow of pressurized water through fracture networks induced in miles-deep hot crystalline rock requires revolutions in two main areas: 1) we must fundamentally understand how fluid pressures and chemical reactions in hot stressed rock alter flow pathways from the micro- to field-scales, and 2) develop new geophysical sensing tools to remotely detect those changes in real-time. To make advances on both fronts, CUSSP integrates a highly instrumented field-scale EGS testbed at the Sanford Underground Research Facility (SURF) established by DOE’s Geothermal Technologies Office (GTO) in combination with core-to-microscale laboratory experiments and multi-continuum and molecular reactive flow simulations.
Using chemically-controlled circulation tests at the testbed, CUSSP is developing the ability to reconstruct the spatiotemporal distribution of reactive fracture flow properties through joint inversions of time-lapse distributed seismic, strain, and temperature sensing with electrical resistivity tomography (ERT) for novel insights into changes in porosity, stress, and fluid chemistry. This entails developing enhanced strainmeter and ERT sensing capabilities, performing machine learning (ML) analyses of seismic datasets from previous testbed experiments to understand how changes in the coda signal relate to strain in pressurized fractures, enhancing the coupling of geophysical process models in our primary simulator PFLOTRAN, characterizing the petrographic, mineralogic, and geomechanical properties of the testbed host rock from the micro- to core-scale to inform reactive flow simulations, training ML algorithms to guide joint inversions to physically meaningful solutions, and implementing efficient coarse-grained modeling techniques to simulate interfacial reaction dynamics between pore fluids and mineral surfaces in the host rock over timescales relevant to our upcoming testbed experiments.
The project is well on its way of ultimately setting a new standard in the ability to predict and control fluid flow through EGS fracture networks, and in doing so will help pave the way to seeing below ground with unprecedented precision.
Biosketch: Dr. Kevin Rosso is a Laboratory Fellow and the Associate Director of the Physical Sciences Division for Geochemistry at PNNL. He leads the U.S. Department of Energy (DOE) Basic Energy Sciences Geosciences program at PNNL, and is the Director of the Center for Understanding Subsurface Signals and Permeability, a 10-institution Energy Earthshot Research Center funded by DOE’s Office of Science. Dr. Rosso is a well-recognized expert in uncovering mechanisms controlling reaction kinetics at mineral/fluid interfaces, such as for dissolution/precipitation, metal adsorption or incorporation, and electron transfer processes. His work has been applied to a diversity of topics such as metal sulfide oxidation, bacterial reduction of metal oxides, contaminant fate and transport, crystal growth and dissolution, geologic carbon sequestration, electrical energy storage, and stress corrosion cracking.
Dr. Rosso won the Mineralogical Society of America Award in 2004, the Hallimond Lectureship from the Mineralogical Society of Great Britain and Ireland in 2016, and the Stumm Medal from the European Association of Geochemistry (EAG) in 2020. He is a Fellow of the Geochemical Society, the EAG, the American Association for the Advancement of Science, and the American Geophysical Union. His research is compiled in over 430 publications with an H index of 81 (Google Scholar). He has been an active mentor for 50 post-doctoral researchers, graduate students, and early career scientists at PNNL and abroad.
