Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
A Comparison Of The Seismic Full Waveform Inversion Technique To Conventional Methods For The Detection Of Underground Mine Voids
Download A Comparison Of The Seismic Full Waveform Inversion Technique To Conventional Methods For The Detection Of Underground Mine Voids full books in PDF, epub, and Kindle. Read online A Comparison Of The Seismic Full Waveform Inversion Technique To Conventional Methods For The Detection Of Underground Mine Voids ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis A Comparison of the Seismic Full Waveform Inversion Technique to Conventional Methods for the Detection of Underground Mine Voids by : Brian K. Logston
Download or read book A Comparison of the Seismic Full Waveform Inversion Technique to Conventional Methods for the Detection of Underground Mine Voids written by Brian K. Logston and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new surface-based geophysical method of subsurface exploration, Seismic Full Waveform Inversion (FWI) was compared to two other traditionally used surface-based geophysical methods, Electrical Resistivity and Microgravity. The Seismic FWI method was shown to be capable of identifying subsurface anomalies, in this case, flooded underground mine workings, in the geologic setting of this particular site, with less limitations than the other two techniques. This was field verified with confirmation drilling of suspect anomalies and non-suspect locations and down the borehole sonar mapping of the mine workings when encountered. However, it should be noted, that the Seismic FWI method is nearly twice the cost of the other two geophysical methods.
Book Synopsis Comparison of Seismic Inversion Methods on a Single Real Data Set by : Robert G. Keys
Download or read book Comparison of Seismic Inversion Methods on a Single Real Data Set written by Robert G. Keys and published by SEG Books. This book was released on 1998 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Full Waveform Inversion by Model Extension by : Guillaume Camille Michel Barnier
Download or read book Full Waveform Inversion by Model Extension written by Guillaume Camille Michel Barnier and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic imaging is an effective method to produce accurate maps of the Earth's subsurface, and has been employed for decades in global seismology, hydrocarbon exploration, geothermal energy production, and more recently CO2 sequestration and monitoring. In complex geological settings, the quality of such maps highly depends on having a reliable seismic velocity model, which can be difficult to obtain. In this thesis, I develop a novel method, namely full waveform inversion by model extension (FWIME), designed to produce accurate acoustic velocity models of the subsurface from seismic recordings when conventional methods fail. I leverage the robust convergence properties of wave-equation migration velocity analysis (WEMVA) with the accuracy and high-resolution nature of acoustic full waveform inversion (FWI) by combining these techniques into a compact, mathematically consistent, and user-friendly workflow. By doing so, I mitigate the need for accurate initial models and the presence of coherent long-offset and/or low-frequency energy within the recorded data, which are difficult and costly to acquire but often necessary for conventional methods to succeed. The novelty of my method resides in the design of a custom loss function and the optimization strategy I develop to pair WEMVA with FWI, which is more efficient and powerful than applying each method separately or sequentially. I illustrate the potential of my proposed method by accurately inverting datasets generated by realistic 2D benchmark models which simulate complex and challenging geological scenarios encountered in field applications. In each scenario, the dataset lacks low-frequency energy and the initial velocity model is inaccurate, which prevents conventional methods from recovering useful solutions. In addition, I develop an efficient 3D numerical implementation of FWIME with the use of general-purpose graphics processing units (GPU) to handle 3D field datasets containing tens of terabytes of information, and to recover billions of unknown parameters. I successfully apply FWIME to a 3D ocean-bottom-node dataset acquired by Shell in the Gulf of Mexico. I show that my method outperforms conventional FWI and manages to improve the velocity model and the resulting subsurface image quality.
Book Synopsis Detection of Subsurface Cavities by : Edward R. Bates
Download or read book Detection of Subsurface Cavities written by Edward R. Bates and published by . This book was released on 1973 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research has been in progress since July 1970 to determine which geophysical and remote-sensing methods offer the most promising results for detecting subsurface cavities and what might be done to further develop them. Through extensive field tests, it has been determined that none of the standard electrical resistivity procedures give consistently good results. As a result of the initial field testing, a new process of data interpretation has been developed for one specific electrode configuration. Cavities less than 10 feet in diameter and at the depths greater than 100 feet were located. Research is continuing to adapt this process for locating water- or mud-filled cavities.
Book Synopsis High Frequency 3-Component Waveform Inversion for Source and Structural Parameters by :
Download or read book High Frequency 3-Component Waveform Inversion for Source and Structural Parameters written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of three studies to develop and verify techniques to classify weak seismic events. (1) The method and results of full waveform inversion for both detailed source parameters and structure parameters are described. Input data were seismograms from industrial explosions in Eastern Kazakhstan recorded by the NRDC seismic network in 1987. Very good fits were produced between the synthetic seismograms and the observed data on all three components simultaneously and for P-wave, Rayleigh wave, and Love wave. We interpreted some of the inverted source parameters as characteristic of several different types of industrial surface mining operations. (2) The same technique was used to determine detailed source and structure parameters using an event that is highly relevant to nuclear monitoring. We determined that a salt mine collapse near Solikamsk, the Ural Mountains on 5 January 1995 was most likely a mine collapse instead of an underground explosions. (3) This study was carried out jointly by the Seismology Group of the University of Colorado and the Russian team from the Int'l Institute of Earthquake Prediction Theory and Math. Geophysics. We developed a new technique to identify a seismic event based on simultaneous inversion of surface wave amplitude spectra and signs of first motions of body wave. We applied this technique to several events near the Chinese test site at Lop Nor and demonstrated significant differences in source parameters characterizing explosions and natural earthquakes in this region.
Book Synopsis Interpretation-based Full Waveform Inversion by : David P. Graham
Download or read book Interpretation-based Full Waveform Inversion written by David P. Graham and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Full waveform inversion (FWI) is an iterative seismic data-fitting procedure used to resolve geologically complex subsurface property models. Inverting low-frequency components of the seismic wavefield to update velocity models has been shown to provide significant uplift to image quality during seismic processing but lacks sufficient resolution to be directly interpretable. Recent studies have shown that higher-frequency inversions can highlight interpretable features that can aid hydrocarbon exploration and reveal shallow geohazards among other applications. High-resolution models obtained from FWI have the potential to aid quantitative interpretation at stratigraphic and reservoir scales, but the accuracy and practical limitations of high-frequency seismic inversions remain an active research topic at the time of writing. To investigate, we perform acoustic FWI on a geologically realistic earth modeled data set created by the Western Australia Modeling Project. The earth model was built from field data and captures the seismic imaging challenges of the Northern Carnarvon Basin, on the Northwest Shelf of Australia. The inversion is performed as a blind test that mitigates bias and simulates a seismic exploration scenario. Throughout the workflow and inversion, initial estimates and model updates, respectively, are constrained by interpretation concepts in the model and data domains. Results demonstrate that interpretation concepts aid convergence to geologic property models and reduce the inherent non-uniqueness of FWI. Furthermore, the resulting inversion provides an opportunity to evaluate the potential benefits and limitations of directly interpretable models produced from acoustic FWI.
Book Synopsis Shape Based Methods for Seismic Full-waveform Inversion by : Yifan Wu
Download or read book Shape Based Methods for Seismic Full-waveform Inversion written by Yifan Wu and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Use of Electrical Resistivity to Detect Underground Mine Voids in Ohio by : Rodney Allen Sheets
Download or read book Use of Electrical Resistivity to Detect Underground Mine Voids in Ohio written by Rodney Allen Sheets and published by . This book was released on 2005 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project was a natural extension of the 1996-1997 void detection work completed by the USGS for ODOT. This earlier project was entitled "Detection of Underground Mine Voids in Ohio by Use of Geophysical Methods" and was published as U.S. Geological Survey (USGS) Water-Resources Investigations Report # 97-4221. This report discussed several possible geophysical techniques that might be successful at detecting mine voids. The only geophysical technique tested during this earlier research project was ground penetrating radar. The report indicated that the likelihood of detecting variations in electrical resistivity due to the presence of abandoned underground mine voids was sufficient to warrant further investigation. The approach for the current research project reflects the proposed completion of the investigation of electrical resistivity measurements for this purpose. This proposed research approach would benefit the Office of Geotechnical Engineering as a continuation of research related to finding effective.
Book Synopsis Three Dimensional Visco-acoustic Frequency Domain Full Waveform Inversion by : Hafedh Ben Hadj Ali
Download or read book Three Dimensional Visco-acoustic Frequency Domain Full Waveform Inversion written by Hafedh Ben Hadj Ali and published by . This book was released on 2009 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: In seismic exploration, it is crucial to extract from the recorded data the physical of the subsurface in order to correctly locate the potential reservoirs. In this context, seismic imaging is an important step in this quest. The imaging process has been for a long time based on a two-scale strategy : the first step consists in building a smooth velocity model, which correctly explains the kinematics, and the second step in taking into account the dynamics through a migration process to detect reflectivity contrasts. In the eighties, a quantitative imaging method, called waveform inversion, has been proposed to bring together the two stages in an integrated approach. The objective of waveform inversion is to build the whole spectrum of wavenumbers by exploiting all the recorded arrivals acquired by wide aperture acquisitions. The method is formulated as a least squares optimization problem which aims to minimize the differences between the recorded and the modelled data. During the last few years, the waveform inversion method has been a main research topic in the academic and industrial communities. Many issues related to the starting anisotropy and elasticity, and the transition from 2-D to 3-D have been investigated. In this context, the objective of this thesis is to investigate and to develop a waveform inversion approach in the frequency domain and within the visco-acoustic approximation for the reconstruction of a 3-D subsurface model where the model is parametrized by the P-waves velocity, density and attenuation.
Book Synopsis A Comparison of Seismic and Resistivity Methods with Conventional Subsurface Investigation by : David Francis Mezera
Download or read book A Comparison of Seismic and Resistivity Methods with Conventional Subsurface Investigation written by David Francis Mezera and published by . This book was released on 1966 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rock Fractures and Fluid Flow by : National Research Council
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 1996-08-27 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.
Book Synopsis Passive Seismic Interferometry in the Real World by : Yang Zhao
Download or read book Passive Seismic Interferometry in the Real World written by Yang Zhao and published by . This book was released on 2013 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade witnessed rapid development of the theory of passive seismic interferometry followed by numerous applications of interferometric approaches in seismic exploration and exploitation. Developments conclusively demonstrates that a stack of cross-correlations of traces recorded by two receivers over sources appropriately distributed in three-dimensional heterogeneous earth can retrieve a signal that would be observed at one receiver if another acted as a source of seismic waves. The main objective of this dissertation was to review the mathematical proof of passive seismic interferometry, and to develop innovative applications using microseismicity induced by hydraulic fracturing and near-surface void characterization. We began this dissertation with the definitions and mathematical proof of Green's function representation, together with the description of the physical mechanisms of passive seismic interferometry. Selected computational methods of passive seismic interferometry are also included. The first application was to extract body waves and perform anisotropy analysis from passive downhole microseismic noise acquired in hydrocarbon-bearing reservoirs. We demonstrate the ability to retrieve various cross-well and VSP-type data from noise for a number of acquisition geometries, providing crucial information for constructing velocity models and estimating local stress/strain and anisotropic parameters. An important advantage compared to traditional studies of microseismicity induced by hydraulic fracturing appear to possess wide spatial apertures, allowing the successful reconstruction of waves that travel directly between the downhole receivers. The second application is to image subsurface voids by measuring variations in the amplitude of seismic surface waves generated by motor vehicles. Our key innovation is based on the cross-correlation of surface wavefields and studying the resulting power spectra, looking for shadows caused by the scattering effects of a void. We are able to conclude that measuring scattered surface waves generated by motor vehicles is a better tool for finding underground voids comparing to conventional techniques based on phase/amplitude distortion using active sources. We expect the number of applications of passive interferometry in microseismic/near surface characterization to grow once practitioners recognize its value and begin using the method.
Book Synopsis Seismic 'Full Waveform Inversion' of Wrapped and Unwrapped Phase by : Nikhil Shah
Download or read book Seismic 'Full Waveform Inversion' of Wrapped and Unwrapped Phase written by Nikhil Shah and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Efficient Inversion Methods for Constrained Parameter Identification in Full-Waveform Seismic Tomography by : Christian Böhm
Download or read book Efficient Inversion Methods for Constrained Parameter Identification in Full-Waveform Seismic Tomography written by Christian Böhm and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Modeling of Seismic Wave Propagation in Underground Mines by : Xin Wang
Download or read book Numerical Modeling of Seismic Wave Propagation in Underground Mines written by Xin Wang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The phenomenon of rockburst damage localization, which is not well understood, has been observed in deep underground mines. Analysis of seismic wave propagation in underground mines is of great interest for improved understanding of the dynamic rock failure problem. This thesis aims at making a contribution for improving understanding of the seismic wave propagation in deep underground mines. Advanced numerical modeling tools are used and new modeling techniques are developed to attain this goal. In this thesis, research is emphasized on the ground motion around excavations due to seismic wave propagation that results from a fault-slip seismic event in the far-field and the near-field. It is found that moment tensor point source model seems to be suitable for the source representation in the far-field and the non-point source model (such as kinematic rupture source model) seems to be suitable for the source representation in the near-field. The modeling results confirm that ground motion is influenced by many factors such as target-source distance, slip direction, spatial location, and geometrical and geological conditions. Influence of wavelength-to-excavation span (/D) ratio on the wavefield is investigated to gain insights of ground motion behavior under both quasi-static and dynamic loading conditions. It is revealed that PPV (peak particle velocity) values increase as the /D ratio increases and the amplification effect increases as the /D ratio decreases. The loading condition maybe changed from the dynamic loading to the quasi-static condition when the /D is larger than 30. Strong dynamic loading should be considered when the /D ratio is small (less than 10, with a shear wavelength less than 50 m and an excavation span greater than 5 m) for most underground excavations. A method is proposed to estimate the quality factor (a measure of energy loss per oscillation cycle) for shear waves propagating in underground hard rocks so as to gain insight into the influence of internal attenuation on seismic wave propagation. A proper shear wave quality factor can be obtained by comparing modeling results with that from a scaling law, even if there are no high quality data for quality factor back analysis. Furthermore, the influence of different geological structures on seismic wave propagation is studied. It is shown that wave propagation patterns around an excavation can be altered and PPV amplification and shielding effect can occur near the excavation boundaries amongst other reasons due to heterogeneities such as tunnels, open and backfilled stopes, and dykes in underground mines. Finally, a coupled numerical procedure, which couples FLAC and SPECFEM2D, is developed to consider the excavation effect on ground motion. The FLAC model considers the excavationinduced stress change and rock mass failure, and passes the input data to SPECFEM2D by invoking FISH scripts. In addition, a new nonlinear velocity model that considers the influence of confinement and rock mass failure on wave velocity is presented. This nonlinear velocity model and the coupled numerical technique are used to model a simple stope excavation problem. It is found that there is a large difference in the wavefields and ground motions between the results from the uniform and non-uniform velocity models. A relatively stronger amplification is observed in the low confinement zones and on the excavation surface in the non-uniform velocity models. Because stress redistribution and rock mass failure around an excavation are considered, a realistic non-uniform velocity field can be obtained. The proposed coupled numerical procedure offers a method to improve the understanding of the site amplification effect and ground motion near excavation boundaries. This thesis presents some insights with regard to seismic wave propagation due to fault-slip seismic events in underground mines. If seismic wave propagation in underground mines can be modeled properly using techniques such as these presented in this thesis, then it is possible to conduct forensic analysis after a large seismic event so as to explain one of many factors that caused rockburst damage localization. Alternatively, the modeling approach may provide valuable inputs for decision-making with regard to strengthening high risk areas to prevent rockburst, thus improving mine safety.
Book Synopsis Source-independent Full Waveform Inversion of Seismic Data by :
Download or read book Source-independent Full Waveform Inversion of Seismic Data written by and published by . This book was released on 2002 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rigorous full waveform inversion of seismic data has been a challenging subject partly because of the lack of precise knowledge of the source. Since currently available approaches involve some form of approximations to the source, inversion results are subject to the quality and the choice of the source information used. We propose a new full waveform inversion methodology that does not involve source spectrum information. Thus potential inversion errors due to source estimation can be eliminated. A gather of seismic traces is first Fourier-transformed into the frequency domain and a normalized wavefield is obtained for each trace in the frequency domain. Normalization is done with respect to the frequency response of a reference trace selected from the gather, so the complex-valued normalized wavefield is dimensionless. The source spectrum is eliminated during the normalization procedure. With its source spectrum eliminated, the normalized wavefield allows us construction of an inversion algorithm without the source information. The inversion algorithm minimizes misfits between measured normalized wavefield and numerically computed normalized wavefield. The proposed approach has been successfully demonstrated using a simple two-dimensional scalar problem.
Book Synopsis Introduction to seismic inversion methods by : Brian H. Russell
Download or read book Introduction to seismic inversion methods written by Brian H. Russell and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
