Download or read book Imaging Channelized Flow in Fractured Rock Using Surface Ground Penetrating Radar written by and published by . This book was released on 2005 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: An understanding of fluid flow through fractured rock is important for monitoring and predicting contamination in bedrock hydrologic systems. Many lines of evidence suggest that water flows through bedrock fractures in a channelized manner along paths of least hydraulic resistance that are related to both fracture aperture variations and hydraulic influences. The results of this research show, for the first time, direct evidence of flow channeling at the field scale. Experiments were conducted at the Altona Flat Rocks site near Plattsburgh, New York using surface ground penetrating radar (GPR) to detect electrically conductive saline tracer moving through a sub-horizontal bedding plane fracture under various flow conditions. The theoretical basis for these experiments is the known variation in reflectivity of electromagnetic waves between fractures filled with water versus fractures filled with high-salinity tracer. Results show that hydrogeophysical investigations using GPR can successfully image tracer migration in a variety of flow configurations through both space and time. Flow channeling behaviors observed in map view images of tracer migration demonstrate meter-scale variability that can be attributed to the spatial distribution of fracture aperture.
Download or read book Recover Act Verification of Geothermal Tracer Methods in Highly Constrained Field Experiments written by and published by . This book was released on 2014 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The prediction of the geothermal system efficiency is strong linked to the character of the flow system that connects injector and producer wells. If water flow develops channels or "short circuiting" between injection and extraction wells thermal sweep is poor and much of the reservoir is left untapped. The purpose of this project was to understand how channelized flow develops in fracture geothermal reservoirs and how it can be measured in the field. We explored two methods of assessing channelization: hydraulic connectivity tests and tracer tests. These methods were tested at a field site using two verification methods: ground penetrating radar (GPR) images of saline tracer and heat transfer measurements using distributed temperature sensing (DTS). The field site for these studies was the Altona Flat Fractured Rock Research Site located in northeastern New York State. Altona Flat Rock is an experimental site considered a geologic analog for some geothermal reservoirs given its low matrix porosity. Because soil overburden is thin, it provided unique access to saturated bedrock fractures and the ability image using GPR which does not effectively penetrate most soils. Five boreholes were drilled in a "five spot" pattern covering 100 m2 and hydraulically isolated in a single bedding plane fracture. This simple system allowed a complete characterization of the fracture. Nine small diameter boreholes were drilled from the surface to just above the fracture to allow the measurement of heat transfer between the fracture and the rock matrix. The focus of the hydraulic investigation was periodic hydraulic testing. In such tests, rather than pumping or injection in a well at a constant rate, flow is varied to produce an oscillating pressure signal. This pressure signal is sensed in other wells and the attenuation and phase lag between the source and receptor is an indication of hydraulic connection. We found that these tests were much more effective than constant pumping tests in identifying a poorly connected well. As a result, we were able to predict which well pairs would demonstrate channelized flow. The focus of the tracer investigation was multi-ionic tests. In multi-ionic tests several ionic tracers are injected simultaneously and the detected in a nearby pumping well. The time history of concentration, or breakthrough curve, will show a separation of the tracers. Anionic tracers travel with the water but cationic tracer undergo chemical exchange with cations on the surface of the rock. The degree of separation is indicative of the surface area exposed to the tracer. Consequently, flow channelization will tend to decrease the separation in the breakthrough. Estimation of specific surface area (the ration of fracture surface area to formation volume) is performed through matching the breakthrough curve with a transport model. We found that the tracer estimates of surface area were confirmed the prediction of channelized flow between well pairs produced by the periodic hydraulic tests. To confirm that the hydraulic and tracer tests were correctly predicting channelize flow, we imaged the flow field using surface GPR. Saline water was injected between the well pairs which produced a change in the amplitude and phase of the reflected radar signal. A map was produced of the migration of saline tracer from these tests which qualitatively confirmed the flow channelization predicted by the hydraulic and tracer tests. The resolution of the GPR was insufficient to quantitatively estimate swept surface area, however. Surface GPR is not applicable in typical geothermal fields because the penetration depths do not exceed 10's of meters. Nevertheless, the method of using of phase to measure electrical conductivity and the assessment of antennae polarization represent a significant advancement in the field of surface GPR. The effect of flow character on fracture / rock thermal exchange was evaluated using heated water as a tracer. Water el ...
Download or read book Rock Fractures and Fluid Flow written by National Research Council and published by National Academies Press. This book was released on 1996-09-27 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientific understanding of fluid flow in rock fracturesâ€"a process underlying contemporary earth science problems from the search for petroleum to the controversy over nuclear waste storageâ€"has grown significantly in the past 20 years. This volume presents a comprehensive report on the state of the field, with an interdisciplinary viewpoint, case studies of fracture sites, illustrations, conclusions, and research recommendations. The book addresses these questions: How can fractures that are significant hydraulic conductors be identified, located, and characterized? How do flow and transport occur in fracture systems? How can changes in fracture systems be predicted and controlled? Among other topics, the committee provides a geomechanical understanding of fracture formation, reviews methods for detecting subsurface fractures, and looks at the use of hydraulic and tracer tests to investigate fluid flow. The volume examines the state of conceptual and mathematical modeling, and it provides a useful framework for understanding the complexity of fracture changes that occur during fluid pumping and other engineering practices. With a practical and multidisciplinary outlook, this volume will be welcomed by geologists, petroleum geologists, geoengineers, geophysicists, hydrologists, researchers, educators and students in these fields, and public officials involved in geological projects.
Download or read book Field Experiments for Fracture Characterization written by Nedra Danielle Bonal and published by . This book was released on 2007 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Treatise on Water Science written by and published by Newnes. This book was released on 2010-09-01 with total page 2131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water quality and management are of great significance globally, as the demand for clean, potable water far exceeds the availability. Water science research brings together the natural and applied sciences, engineering, chemistry, law and policy, and economics, and the Treatise on Water Science seeks to unite these areas through contributions from a global team of author-experts. The 4-volume set examines topics in depth, with an emphasis on innovative research and technologies for those working in applied areas. Published in partnership with and endorsed by the International Water Association (IWA), demonstrating the authority of the content Editor-in-Chief Peter Wilderer, a Stockholm Water Prize recipient, has assembled a world-class team of volume editors and contributing authors Topics related to water resource management, water quality and supply, and handling of wastewater are treated in depth
Download or read book Ground penetrating Radar for Geoarchaeology written by Lawrence B. Conyers and published by John Wiley & Sons. This book was released on 2016-01-19 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has long been a strong collaboration between geologists and archaeologists, and the sub-field of geoarchaeology is well developed as a discipline in its own right. This book now bridges the gap between those fields and the geophysical technique of ground-penetrating radar (GPR), which allows for three-dimensional analysis of the ground to visualize both geological and archaeological materials. This method has the ability to produce images of the ground that display complex packages of materials, and allows researchers to integrate sedimentary units, soils and associated archaeological features in ways not possible using standard excavation techniques. The ability of GPR to visualize all these buried units can help archaeologists place ancient people within the landscapes and environments of their time, and understand their burial and preservation phenomena in three-dimensions. Readership: Advanced students in archaeology and geoarchaeology, as well as practicing archaeologists with an interest in GPS techniques.
Download or read book Use of Airborne Surface and Borehole Geophysical Techniques at Contaminated Sites written by and published by . This book was released on 1993 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Imaging Elastodynamic and Hydraulic Properties of Fractured Rock written by Clay Wood and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic perturbations in the subsurface, originating from natural or industrial sources, are associated with observations of changes in poro-elastic properties that have far-ranging effects. Broadly, there are "strain-induced" and "fluid-induced" sources of these subsurface perturbations and, importantly, they produce coupled phenomenological observations. Many experimental and numerical studies that quantify elastic and hydraulic properties of rock, fractured (or ``intact'') under static stress conditions, however these measures are not necessarily indicative of their response during dynamic stress conditions. Motivated by these field observations, I use simultaneous continuous fluid flow and ultrasonic monitoring to quantify the elastic and permeability changes of natural and rough fractures. Furthermore, I incorporate measures of fracture topology and contact area to connect to the spatially variable ultrasonic monitoring and as inputs for multiphysics modeling of a single planar fracture. In this dissertation, I ask fundamental questions surrounding the connection between fracture specific stiffness and fluid transport under a range of loading conditions and dynamic stressing. Moreover, I do so by performing complex experiments under triaxial stresses and use simultaneous continuous active-source ultrasonic monitoring and fluid flux measurements to measure the static and dynamic elastic and hydraulic properties of fractures. These unique experiments are also complemented by post-surface and topography characterization using pressure registering films and profilometry. I begin this dissertation by introducing the problem statement broadly and providing some context for field-scale observations of dynamic stress-induced changes in the subsurface and lay out the limitation of linear elastic work within this context. In Chapter 2, I use ultrasonic monitoring to image the spatial and elastic variability across an in-situ fractured rock specimen and relate these to fluid flow. These experiments produced complex results which highlights the variable nature of sheared fractured rock. In Chapters 3 and 4, I extend the work of Chapter 1 by focusing on the effect of stress state on dynamic stress-induced changes in flow and elasticity. Chapter 3 demonstrates the systematic reduction in nonlinear elasticity and permeability enhancement with increasing stress state, simulating depths. I additionally relate the real contact area from pressure sensitive films to the documented elastodynamic changes. Chapter 4 leverages the experimental results from Chapter 3 and utilizes high-resolution profilometry of the tensile fracture specimen as an input for multiphysics modeling. I demonstrate that perfectly matched fracture surfaces can reproduce some of the static fluid flow properties and that misalignment is highly influential on overall poro-elastic properties. Chapter 5 represents a focused study on the relation between roughness and granular in-fill of planar fractures and their influence on elastodynamic and hydraulic changes.
Download or read book Using Radar Tomography Tracer Experiments and Hydraulic Data to Characterize Fractured Rock Flow Systems written by Frederick D. Day-Lewis and published by . This book was released on 2000 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Near Surface Geophysics written by and published by . This book was released on 2009 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization Modeling Monitoring and Remediation of Fractured Rock written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2021-01-29 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractured rock is the host or foundation for innumerable engineered structures related to energy, water, waste, and transportation. Characterizing, modeling, and monitoring fractured rock sites is critical to the functioning of those infrastructure, as well as to optimizing resource recovery and contaminant management. Characterization, Modeling, Monitoring, and Remediation of Fractured Rock examines the state of practice and state of art in the characterization of fractured rock and the chemical and biological processes related to subsurface contaminant fate and transport. This report examines new developments, knowledge, and approaches to engineering at fractured rock sites since the publication of the 1996 National Research Council report Rock Fractures and Fluid Flow: Contemporary Understanding and Fluid Flow. Fundamental understanding of the physical nature of fractured rock has changed little since 1996, but many new characterization tools have been developed, and there is now greater appreciation for the importance of chemical and biological processes that can occur in the fractured rock environment. The findings of Characterization, Modeling, Monitoring, and Remediation of Fractured Rock can be applied to all types of engineered infrastructure, but especially to engineered repositories for buried or stored waste and to fractured rock sites that have been contaminated as a result of past disposal or other practices. The recommendations of this report are intended to help the practitioner, researcher, and decision maker take a more interdisciplinary approach to engineering in the fractured rock environment. This report describes how existing tools-some only recently developed-can be used to increase the accuracy and reliability of engineering design and management given the interacting forces of nature. With an interdisciplinary approach, it is possible to conceptualize and model the fractured rock environment with acceptable levels of uncertainty and reliability, and to design systems that maximize remediation and long-term performance. Better scientific understanding could inform regulations, policies, and implementation guidelines related to infrastructure development and operations. The recommendations for research and applications to enhance practice of this book make it a valuable resource for students and practitioners in this field.
Download or read book Digital Spectrophotometric Imaging of Two phase Flow in Fractured Rock written by Viktoria Zoltay and published by . This book was released on 2000 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geotechnical Engineering of Dams 2nd Edition written by Robin Fell and published by CRC Press. This book was released on 2014-11-21 with total page 1384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geotechnical Engineering of Dams, 2nd edition provides a comprehensive text on the geotechnical and geological aspects of the investigations for and the design and construction of new dams and the review and assessment of existing dams. The main emphasis of this work is on embankment dams, but much of the text, particularly those parts related to geology, can be used for concrete gravity and arch dams. All phases of investigation, design and construction are covered. Detailed descriptions are given from the initial site assessment and site investigation program through to the preliminary and detailed design phases and, ultimately, the construction phase. The assessment of existing dams, including the analysis of risks posed by those dams, is also discussed. This wholly revised and significantly expanded 2nd edition includes a lengthy new appendix on the assessment of the likelihood of failure of dams by internal erosion and piping. This valuable source on dam engineering incorporates the 200+ years of collective experience of the authors in the subject area. Design methods are presented in combination with their theoretical basis, to enable the reader to develop a proper understanding of the possibilities and limitations of a method. For its practical, well-founded approach, this work can serve as a useful guide for professional dam engineers and engineering geologists and as a textbook for university students.
Download or read book Techniques of Near surface Seismic and Ground penetrating Radar Imaging written by Lars Nielsen and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Observation of Subsurface Flow from the Surface written by Niklas Allroggen and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Using Ground Penetrating Radar GPR for Identifying Floodplain and Riverbed Structural Heterogeneity and Implications for Groundwater surface Water Exchange written by Rebwar Nasir Dara and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
