סמינר מחלקתי של יבגני שבלצון- תיאור התפתחות של נתיבי זרימה מועדפים במהלך הזרקה בלחץ של נוזל ריאקטיבי כימית לתוך תת-הקרקע באמצעות תרמודינמיקה שאינה בשיווי משקל
Describing evolution of preferential flow paths during pressurized injection of chemically
reactive fluid into subsurface using non-equilibrium thermodynamics
Thursday August 21th 2025 at 14:00
Wolfson Building of Mechanical Engineering, Room 206
:Abstract
Pressurized injection of chemically reactive fluid into underground rocks is ubiquitous in geophysical applications such as subsurface carbon sequestration, hydraulic fracturing and wastewater disposal, leading to flow-induced deformation of the rock, accompanied by chemical weathering. Both these processes, acting individually or coupled together, lead to alteration of transport properties of the rock and facilitate emergence and intensification of preferential flow paths, characterized by gradients of hydrodynamic pressure and solute concentration. Since these paths dominate the multiscale transport dynamics, control the nature of poromechanical and reaction-transport coupling and determine the overall efficiency of the process, understanding their role in subsurface transport following pressurized fluid injection is essential to ensure safety, efficiency and control throughout the process.
As a case study, we consider pressurized injection of acidic fluid into calcite porous rock leading to poromechanical deformation of the rock, accompanied by a reversible dissolution-precipitation reaction, simulated numerically using in-house created models. We apply non-equilibrium thermodynamic framework to analyze the ensuing complex interaction between flow-induced deformation, chemical reaction and transport in this geophysical scenario. To this end, we identify the entropy generation sources, attributed to pertinent dissipative processes and show a clear correlation between the emergence and intensification of preferential flow paths and the accompanying dissipative dynamics, where the evolution of emerging paths leads to a decrease in the free-energy dissipation in the system. This indicates that the emergence of preferential flow paths in geophysical systems represents an energetically-preferred state of the system and can be considered a manifestation of the minimum energy dissipation principle. The developed concepts may assist in determining optimal conditions for pressurized fluid injection into subsurface, as well as in geophysical dating.
Bio:
Evgeny Shavelzon is a Ph.D candidate in Environmental Engineering at the Technion – Israel Institute of Technology under the advision of Dr. Yaniv Edery (Porous Media Visualized lab). His current research topics include numerical modeling of nonequilibrium processes in heterogeneous porous media in application to Geophysics and application of nonequilibrium thermodynamic framework for their characterization. Coming from Aerospace / Mechanical Engineering field, Evgeny’s previous research focused on developing numerical methods for solution of PDE. His goal during Ph.D is to apply and expand this previously acquired knowledge to modeling and understanding complex subsurface transport processes. Following the publication of his first Ph.D paper, Evgeny has received the Jacobs award for an outstanding research paper. Besides academic research, Evgeny has a significant experience in the industry as a Computational Mechanics analyst working on development and implementation of numerical methods in the field of Fluid mechanics, Poroelasticity, Chemical kinetics, Structural mechanics, Heat transfer, and Optics.
