Parallel Session

Special Sessions
  • 1.Scientific machine learning applications for coupled processes in the subsurface Detail

    • Session Description:
      Despite the significant amount of works, our current understanding of coupled thermal-hydrological-mechanical-chemical (THMC) processes in the subsurface is still inadequate to effectively characterize, predict, or control multiphysics processes with confidence or in real-time as a result of the heterogeneity and coupled THMC processes. A recent big wave in machine learning has led to massive successes by leveraging large amounts of training data and advancing the machine learning algorithms. In particular, deep learning methods have been greatly advanced to efficiently extract information, discover knowledge, and identify correlations and patterns. Problems in the coupled processes in the subsurface are also amenable to machine learning, but they have unique challenges and opportunities that need to be overcome by incorporating our established domain knowledge/models based on physical mechanisms and scientific knowledge. The purpose of this special session is to bring the latest theoretical, algorithmic, and practical advancements of machine learning to the coupled processes and how we can complement traditional domain models by incorporating our physics-based knowledge into the machine learning (e.g., physics-informed/scientific machine learning) and artificial intelligence. This special session aims to advance deep learning and various machine learning methods with our knowledge of the coupled processes in terms of various data type and volume, modeling and simulations, and physical principles and constraints.
    • Conveners:
      Hongkyu Yoon, Sandia National Laboratories
      Hoonyoung Jeong, Seoul National University
  • 2.Development of coupled processes and their validation in nuclear wastes disposal(DECOVALEX) Detail

    • Session Description:
    • Conveners:
      Alex Bond, Quintessa, UK
      Changsoo Lee, Korea Atomic Energy Research Institute, Korea
General Sessions
  • 1.Coupled Thermo-Hydro-Mechanical-Chemical (THMC) processes in single fractures Detail

    • Session Description:
      A better understanding of the coupled THMC processes in single rock fractures is fundamental for accurately predicting the coupled THMC processes in fractured rock masses. Even though numerous experimental and numerical studies have been performed to investigate the coupled THMC processes in single rock fractures, and a large number of empirical or analytical models have been proposed to describe the interaction between the THMC processes in single fractures. However, there exist many open questions on the coupled THMC processes in single rock fractures, including but not limited to the effect of surface roughness on heat and mass transfer through rock fractures, the thermal effects on geometric and mechanical of rock fractures, the complex water-rock interaction in fractures. Therefore, we propose this this session to welcome papers discussing the fundamental mechanisms, multi-scale observation, theoretical models, and numerical modeling of the coupled THMC processes in single rock fractures.
    • Conveners:
      Zhihong Zhao, Tsinghua University
      Yuedu Chen, Tsinghua University
  • 2.Advances in computation of coupled processes in fractured media across scales: numerical modeling and machine learning Detail

    • Session Description:
      With the advances in computational capabilities, numerical methods and machine learning algorithms emerge as important approaches for analyzing geoscience processes. In this session, we welcome papers discussing the development and application of numerical methods and machine learning algorithms that can address fundamental as well as large-scale behavior involving coupled processes in fractured geological media. 
      The numerical methods could include (but not limited to): finite element, finite volume, finite difference, phase field approaches; boundary element approaches; discrete element, discontinuous deformation analysis approaches; finite-discrete element approaches; extended finite element, generalized finite element, partition of unity, meshfree/meshless, numerical manifold approaches. 
      Supervised or unsupervised machine learning in combination with measured data and/or numerical modeling for predicting coupled process behavior are welcome to present, including (but not limited to): support vector machines, artificial neural networks, deep neural networks, clustering.
    • Conveners:
      Mengsu Hu, Lawrence Berkeley National Laboratory
      Adriana Paluszny, Imperial College London
      Pania Newell, The University of Utah
      Shaojun Li, Chinese Academy of Sciences
      Laura Blanco Martin, Mines ParisTech
  • 3.Mechanics of induced seismicity: managing complexity from lab to field scale Detail

    • Session Description:
      Forecasting and controlling fluid-injection induced seismicity is an extraordinary challenge: the processes driving the system to failure have characteristic length and time scales that span several orders of magnitude and hinders, in addition to subsurface complexity, any potential deterministic understanding. The process involves changes in temperature, pressure, stress and chemical composition and, though some of the fundamental interactions are known, upscaling and managing topological complexity are still widely open questions. We wish to attract contributions aiming at the integration of experimental evidence, in-situ observations, analytical and numerical insights stemming from theoretical arguments on the coupled thermo-hydro-mechanical-chemical processes that control induced seismicity. Applications include (but are not limited to) carbon capture and storage (CCS), geothermal energy, gas storage, stimulation strategies, hydro-fracturing/shearing and radioactive waste storage. In this session, we welcome contributions that advance the understanding of triggering mechanisms of induced seismicity and present novel methodologies to forecast and mitigate fluid injection induced seismicity.
    • Conveners:
      Víctor Vilarrasa, Spanish National Research Council (CSIC) 
      Roman Makhnenko, University of Illinois at Urbana-Champaign
      Francesco Parisio, Freiberg University of Mining and Technology
  • 4.Coupled multiphysics during coal gas and shale gas extraction Detail

    • Session Description:
      Coal gas and shale gas are very important unconventional energy for future. The efficient gas extraction is dependent on the permeability of the gas reservoirs whenever before and after fracking with different fluids. In addition to the conventional hydro-fracturing with water, other waterless fracking with gases such air, N2, and supercritical CO2 was also been studied. In this regard, the permeability evolution before and after fracking is a complex process, involving interactions among stress, fluid pressure, temperature and phase change, though some of the fundamental interactions are known, upscaling and managing engineering complexity are still widely open questions. We wish to attract contributions aiming at clarifying the multiphysical interactions during coal gas and shale gas extraction. In this session, we welcome contributions that advance the understanding of permeability enhancement induced by fracking of gas reservoirs with different fluids, which includes the work on experimental observation, theoretical solution, numerical simulation and in-situ characterization that related to this topic.
    • Conveners:
      Wancheng Zhu, Northeastern University, China
  • 5.Numerical modelling of long term THM coupled processes in fractured hard rock Detail

    • Session Description:
      A final repository for spent nuclear fuel is a project of unique character. The engineering design is subject to strict requirements and the safety assessment encompasses the next million years. Complex behaviour and coupled processes as well as long term phenomena have to be considered. This encompasses phenomena such us glaciation cycles, permafrost, earthquake, and thermal loading. These phenomena can induce pore pressure changes, deformation and fracturing of the rock mass and, as a consequence, changes in fracture network connectivity and flow and thermal conductivity. Numerical modelling of long term THM coupled processes is therefore a key aspect for the long-term safety assessment of spent nuclear facilities. In this session, we would like to discuss the latest advances in this research area.
    • Conveners:
      Diego Mas Ivars, Swedish Nuclear Fuel and Waste Management Co
  • 6.Coupled THM hard rock fracture behaviour – laboratory experiments and numerical modelling Detail

    • Session Description:
      Flow through fractured hard rock occurs mainly through the fractures. Although coupled single fracture behaviour has been subject to investigation in the latest decades, outstanding questions still remain. Recent improvements in laboratory testing equipment, surface characterization methods, monitoring and visualization techniques allow for a much more detailed study and conceptualization of the coupled THM behaviour of single fractures and fracture intersections. Furthermore, in order to incorporate coupled THM behaviour in discrete modelling methodologies with millions of fractures, the key is to find the balance between constitutive model detail and pragmatic simplification. In this session we would like to discuss these and other questions related to this research area.
    • Conveners:
      Diego Mas Ivars, Swedish Nuclear Fuel and Waste Management Co
  • 7.Coupled THM field experiments in fractured hard rock Detail

    • Session Description:
      Planning, executing and interpreting coupled THM field experiments is a complex task. However, it is the key to understanding the intermediate and large scale coupled THM processes that govern fractured rock mass behaviour. By measuring and/or monitoring the THM response of the rock mass we can improve our understanding and validate existing constitutive models or develop new ones. This, in turn, contributes to increasing the confidence in our predictions and assessments. In this session we would like to discuss about the latest advances in this research area.
    • Conveners:
      Diego Mas Ivars, Swedish Nuclear Fuel and Waste Management Co 
      Shaojun Li, Chinese Academy of Sciences
      Jeoung Seok Yoon, DynaFrax UG
  • 8.Advances in fluid injection induced shear slips on natural fractures Detail

    • Session Description:
      Hydraulic-mechanical interactions on natural fractures have been investigated through multi-scale experiments and numerical modelling in past decades. We realize that hydraulic performance and stability of natural fracture are closely related to intrinsic properties of fractures as well as fluid injection scheme. Are we able to control the shear slip? If yes, how to? In this session we would like to discuss the recent advances related to injection induced shear slips on natural fractures.
    • Conveners:
      Fengshou Zhang, Tongji University
      Li Zhuang, Korea Institute of Civil Engineering and Building Technology
      Takuya Ishibashi, National Institute of Advanced Industrial Science and Technology (AIST)
  • 9.Mechanics of Hydraulic Fracturing in Naturally Fractured Reservoirs Detail

    • Session Description:
      Despite the great commercial success of hydraulic fracturing for unconventional, some fundamental mechanisms associated with hydraulic fracturing in naturally fractured reservoirs have not been well understood yet. This session focuses on the better understanding of some key aspects of hydraulic fracturing, from fracture initiation, propagation, proppant transport, interaction with natural fractures, to the long-term behaviors of hydraulic fractures during and after production. We welcome contributions to discuss the latest advances of analytical, numerical, and experimental analysis in this research area.
    • Conveners:
      Fengshou Zhang, Tongji University
      Li Zhuang, Korea Institute of Civil Engineering and Building Technology
      Takuya Ishibashi, National Institute of Advanced Industrial Science and Technology (AIST)
  • 10.Coupled seismo-thermo-hydro-mechanical-chemical processes in natural fracture networks: from field observation to numerical simulation Detail

    • Session Description:
      Natural fractures widely spread in crustal rocks and often dominate the bulk properties of geological media. Coupled seismo-thermo-hydro-mechanical-chemical processes in fractured rocks are, therefore, significantly influenced by the distribution and behaviour of fracture networks. Thus, it is of central importance to understand the interrelationship between fracture network properties and coupled multiphysical processes (e.g. seismic wave propagation, heat transfer, fluid flow, solute transport, solid deformation and chemical reaction) across various spatial and temporal scales. In this session, we focus on the recent advances in field observation and numerical simulation of coupled processes in naturally fractured rocks at the network or site scale.
    • Conveners:
      Qinghua Lei, ETH Zürich
      Jeoung Seok Yoon, DynaFrax UG
  • 11.Long term behavior of fractured geological media under coupled THMC environment Detail

    • Session Description:
      Study on long term behavior of fractured geological media under coupled thermo-hydro-mechanical-chemical (THMC) environment is important for safety assessment in the applications of high level nuclear waste disposal, hydraulic and hydropower engineering, mining engineering, geological sequestration of carbon dioxide and slope engineering, etc. New advances and insights in the study of long term mechanical and physical behaviors of fractured geological media are welcome. This session calls for abstracts in the related topics on in-situ observations, in lab tests, theoretical analysis and numerical modeling with consideration of TM, THM, HM, HMC or THMC coupling effects in fractured geological media.
    • Conveners:
      Pengzhi Pan, Chinese Academy of Sciences
  • 12.Experimental Studies for Fracture Characterization of Rock across Scales Detail

    • Session Description:
      • · Low and high strain rate,
      • · Utilization of digital image correlations (DIC),
      • · in-situ fracture testing,
      • · High-resolution imaging,
      • · Etc.
    • To be able to predict and control fracture in the subsurface requires fundamental understanding of fracture characterization under both static and dynamic loadings. This session invites experimental investigation of fracture behavior under both individual and coupled processes (thermal, hydrological, mechanical, and chemical-THMC). Topics of interests include but not limited to:
    • Conveners:
      Pania Newell, The University of Utah
  • 13.THMC coupling in geological CO2 storage: from lab to the field scale Detail

    • Session Description:
      Proper characterization of the CO2 storage sites should carefully consider the geomechanical response induced by overpressure and potential fault reactivation that can lead to induced seismicity. On top of that, thermo-mechanical effects play a role because CO2 reaches the storage formation at a colder temperature than that corresponding to the geothermal gradient, which induces thermal stresses. Additionally, CO2 dissolves into in-situ brine, forming carbonic acid that leads to a reduction of the pH and dissolution/precipitation of minerals. These geochemical reactions may alter the geomechanical properties of rocks and faults in the long term. To improve the knowledge and minimize the uncertainty in the short- and long-term subsurface CO2 injection operations, the study of coupled thermo-hydro-mechanical-chemical (THMC) processes at multiple scales is required. These scales comprise core samples tested in the laboratory, field-scale tests performed at pilot test sites, and reservoir-scale characterization related to industrial storage sites. This session is aimed at discussing CO2 storage related THMC coupling at different scales and upscaling of the coupled processes with numerical models.
    • Conveners:
      Roman Makhnenko, University of Illinois at Urbana-Champaign
      Víctor Vilarrasa, Spanish National Research Council (CSIC)
  • 14.Numerical modelling of coupled thermo-hydro-mechanical processes in fractured rocks Detail

    • Session Description:
      Numerical studies of the coupled hydro-mechanical effects in fractured rock masses have been conducted using different methods, such as discrete, continuum and combined continuum-discrete based models. Discrete based models, while more realistic for discontinuous media, have the limitation of being time consuming for modelling the thermo-hydro-mechanical behavior of fractured rock domains with curved or dead-end fractures. Continuum based models require a representation of discrete fracture behavior with appropriate hydro-mechanical properties by an elemental cell, but they can have the advantage of being able to model fractures that are sealed and filled with mineral materials and are less time consuming. Furthermore, important phenomena such as changes in the permeability field and flow paths due to tension failure regions in the intact rock between fractures can be included. In this session, we welcome contributions to improve the existing knowledge on numerical modelling of coupled thermo-hydro-mechanical processes in fractured rocks by using discrete, continuum and combined continuum-discrete based models.
    • Conveners:
      Bruno Figueiredo, Itasca Consultants AB
  • 15.Numerical modelling of coupled thermo-hydro-mechanical processes associated with hydraulically induced fracture propagation Detail

    • Session Description:
      Hydraulic fracturing has been applied to extract oil or gas from shale formations. Numerical continuum- and discrete-based models have been applied to study fracture propagation induced by hydraulic injection pressure. In discrete-based models, the fractures are commonly regarded as mechanical discontinuities with a reduced dimension model for fluid flow in the fractures. Continuum-based models require a representation of discrete fracture behavior in an element cell by appropriate equivalent hydro-mechanical properties. In this session, we welcome submissions of abstracts on numerical modelling by using discrete- and continuum-based models of coupled thermo-hydro-mechanical processes of hydraulic induced fracture propagation and validation against experimental data.
    • Conveners:
      Bruno Figueiredo, Itasca Consultants AB
  • 16.Numerical modelling of the interaction of coupled thermo-hydro-mechanical processes and complex geological settings and heterogeneities Detail

    • Session Description:
      While there have been extensive studies of thermo-hydro-mechanical (THM) processes, their interaction with complex geological settings (fracture networks, bedding planes and pre-existing faults) and heterogeneities (anisotropic in situ stress states, spatial variability of rock mass properties and multi-layers with different hydro-mechanical properties) is still very much an open area of research. The understanding of these interactions is required for several important practical applications: CO2 injection and storage in deep underground formations, hydraulic fracturing to extract oil or gas from shale formations and the geothermal systems. In this session, we welcome contributions in numerical modelling to understand the interaction of coupled THM processes in media with complex geological settings and heterogeneities.
    • Conveners:
      Bruno Figueiredo, Consultants AB
  • 17.Understanding Individual and Coupled Processes through Geo-architected Materials across Scales Detail

    • Session Description:
      The transport of heat and fluids in soils and rocks can be affected by strong coupling between thermal, hydrological, mechanical, and chemical (THMC) processes. However, the existence of fractures across multiple scales make this task very challenging. The significant advances in 3D printing and high-resolution imaging technologies combined with 3D reconstruction techniques provide opportunities to create rock-like samples with similar physical and chemical properties of natural rock with controlled and repeatable heterogeneity. “Geo-architected porous materials” will enable researchers to narrow down the effect of each feature such as pore/fracture size, pore/fracture shape and their distributions on the overall performance of the subsurface under a wide range of thermal, hydraulic, chemical and mechanical conditions. This session will provide a forum for researchers, engineers, and students from diverse disciplines to present their novel approach in understanding individual and coupled processes (THMC) through geo-architected porous materials.
    • Conveners:
      Pania Newell, The University of Utah
  • 18.Advances in discontinuum-based simulation of coupled processes during rock progressive failure Detail

    • Session Description:
      Modelling of rock failure processes represents a challenging task owing to several intrinsic features of the “intact rock”,  including micro crack nucleation, coalescence and growth, non-linear stress-strain response, and confinement dependent characteristics.  At the “rock mass” scale, damage processes are constrained by pre-existing discontinuities, anisotropies and heterogeneities. Furthermore, several geosystems require coupled thermo-hydro-mechanical (THM) models taking into account the interplay between mechanical stresses, fluids, and temperature. With discontinuum-based modelling techniques, commonly referred to as the discrete element method (DEM), the complex behaviour of rocks is captured by a large number of smaller components interacting with each other via relatively simple laws. This session aims to showcase the most recent and exciting developments and applications of such methods, with a particular focus on coupled processes associated with rock progressive failure. Areas of interest include: innovative simulation approaches, multi-physics modelling capabilities, novel application examples, and high performance computing.
    • Conveners:
      Andrea Lisjak, Geomechanica, Inc.
  • 19.THMC coupling in clays Detail

    • Session Description:
      In recent years the scientific community has seen a remarkable surge of interest in the properties and behavior of clays as they apply to a variety of natural and engineered settings. Clays and clayey rocks are key elements in important subsurface energy-related applications, including the long-term disposal of nuclear wastes in geological repositories, the storage of CO2 in subsurface geological formations, and the extraction of energy resources from clay-rich formations (e.g., shale gas). While clay materials offer some striking benefits in these and other applications, their properties and behavior under relevant conditions remain only partly understood. In fact, engineered clay barriers and clay-rocks show a remarkable array of macro-scale properties such as high swelling pressure, very low permeability, semi-permeable membrane properties, and a strong coupling between geochemical, mechanical, and osmotic properties. In this session, we welcome submission of abstracts on experimental, theoretical, and numerical investigations of coupled THMC processes across scales in clay-rich media.
    • Conveners:
      Christophe Tournassat, BRGM & LBNL
      Carl I. Steefel, LBNL
  • 20.Enhanced Geothermal Systems (EGS) Detail

    • Session Description:
      The largest geothermal potential worldwide exists in deep and low permeability formations. In order to exploit this vast resource subsurface fluid pathways need to be engineered. This process typically involves dynamic coupled thermal, hydraulic, mechanical and chemical processes in a heterogeneous and discontinuous medium. To achieve a breakthrough in EGS development worldwide, these processes need to be better understood and controlled. This will enable the development of pioneering reservoir engineering concepts that allow a more controlled and reliable development and operation of EGS. These concepts should focus on achieving a reliable performance increase while minimizing environmental impacts, such as induced seismicity, through pioneering well stimulation methods. 
      This session will showcase the current state of knowledge on coupled processes in EGS through experiments at laboratory, mine and field scale as well as numerical simulations and theoretical considerations.
    • Conveners:
      Hannes Hofmann, Helmholtz Centre Potsdam, GFZ
      Günter Zimmermann, Helmholtz Centre Potsdam, GFZ

CouFrac2020 Best Paper and Poster Award !!

 

Prizes will be awarded to the authors of best papers and posters with certificates.
Recipients will be selected by organizing committee and audience based on scientific contribution and the quality of presentation.

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