Download or read book Complete Anisotropic Analysis of Three Component Seismic Data Related to the Marine Environment and Comparison to Nine Component Land Seismic Data written by Jason Ethan Gumble and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Anisotropic Seismic Structure of the Earth s Mantle written by Eric M. Matzel and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: I have developed a waveform inversion procedure to invert 3 component broadband seismic data for models of the anisotropic seismic structure of the Earth and applied the technique to an investigation of wave propagation through anisotropic media and earthquake data sampling the upper mantle beneath the East European platform. The procedure combines the conjugate-gradient and very fast simulated annealing methods and attempts to minimize a cross-correlation misfit function comparing data to synthetic seismograms. A series of inversion passes are performed over a range of frequency and time windows to progressively focus in on structural details. The intent is to obtain P and S velocity models that simultaneously match all components of the data (radial, vertical and tangential). The variables in the problem are the seismic velocities ([alpha] and [beta]) as a function of depth. When radial anisotropy is required this set is expanded to include the five variables that determine the seismic velocities in a radially anisotropic medium ([alpha subscript h, alpha subscript v, beta subscript h, beta subscript v, eta]). I investigate the propagation of seismic waves through radially anisotropic media, evaluate which elements of radial anisotropy are best resolved by seismic data and discuss strategies for identifying radial anisotropy in the Earth. S anisotropy, [beta]%, and the horizontal component of P velocity, [alpha subscript h], are typically well resolved by multicomponent seismic data. P anisotropy, [alpha]%, and [eta] are often poorly resolved and trade off with one another in terms of their effect on S[subscript V] arrivals. Erroneous structure will be mapped into models if anisotropy is neglected. The size of the erroneous structure will be proportional to the magnitude of anisotropy present and extend well below the anisotropic zone. The effects of anisotropy on P models produced with an isotropic assumption are most similar to the effects on isotropic S[subscript H] models. When comparing isotropic models, [alpha/beta subscript sh] is therefore often a better measure than [alpha/beta subscript sv] for characterizing mantle petrology. Isotropic S[subscript H], S[subscript V] and P models developed separately using the same data set can provide a good initial estimate of the presence, location and magnitude of anisotropy and those results can be used to create an initial model for an anisotropic inversion solving simultaneously for all 3 components of the data. Finally, I present models for the P and S velocity structure of the upper mantle beneath the East European platform including an analysis of radial anisotropy. The data are 3-component broadband seismograms from strike-slip earthquakes located near the edge of the platform and recorded in Russia and Europe. The timing, amplitude and interference characteristics of direct arrivals (S, P), multiply reflected arrivals (SS, PP), converted phases and surface waves provide very good radial resolution throughout the upper 400 km of the mantle. The platform is underlain by a radially anisotropic seismic mantle lid extending to a depth of 200 km with a largely isotropic mantle below. The model has a positive velocity gradient from 41 km to 100 km depth, and a relatively uniform velocity structure from 100 km to 200 km depth with high S[subscript H] and P[subscript H] velocities (4.77 km /s, 8.45 km/s). Shear anisotropy is uniform at 5% ([beta subscript H] > [beta subscript V]) from 41 to 200 km depth, drops to 2% from 200 to 250 km and is isotropic below that. The average shear velocity from 100 to 250 km is also uniform at 4.65 km/s and the drop in anisotropy is matched by a drop in [beta subscript H] to 4.70 km/s combined with an increase in [beta subscript V] to 4.60 km/s. Below 250 km there is a positive velocity gradient in both P and S velocity down to 410 km. P anisotropy is not well resolved, but P structure mimics the S[subscript H] velocity structure, suggesting that P is also anisotropic within the lid.

Download or read book Seismic Signatures and Analysis of Reflection Data in Anisotropic Media written by Ilya Tsvankin and published by SEG Books. This book was released on 2012 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides essential background on anisotropic wave propagation, introduces efficient notation for transversely isotropic (TI) and orthorhombic media, and identifies the key anisotropy parameters for imaging and amplitude analysis. Particular attention is given to moveout analysis and P-wave time-domain processing for VTI and TTI.

Download or read book Analysis of Seismic Anisotropy in 3D Multi component Seismic Data written by Zhongping Qian and published by . This book was released on 2010 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of seismic anisotropy has been recognized by the oil industry since its first observation in hydrocarbon reservoirs in 1986, and the application of seismic anisotropy to solve geophysical problems has been keenly pursued since then. However, a lot of problems remain, which have limited the applications of the technology. Nowadays, more and more 3D multi-component seismic data with wide-azimuth are becoming available. These have provided more opportunities for the study of seismic anisotropy. My thesis has focused on the study of using seismic anisotropy in 3D multi-component seismic data to characterize subsurface fractures, improve converted wave imaging and detect fluid content in fractured reservoirs, all of which are important for fractured reservoir exploration and monitoring. For the use of seismic anisotropy to characterize subsurface fracture systems, equivalent medium theories have established the link between seismic anisotropy and fracture properties. The numerical modelling in the thesis reveals that the amplitudes and interval travel-time of the radial component of PS converted waves can be used to derive fracture properties through elliptical fitting similar to P-waves. However, sufficient offset coverage is required for either the P- or PS-wave to reveal the features of elliptical variation with azimuth. Compared with numerical modelling, seismic physical modelling provides additional insights into the azimuthal variation of P and PS-wave attributes and their links with fracture properties. Analysis of the seismic physical model data in the thesis shows that the ratio of the offset to the depth of a target layer (offset-depth ratio), is a key parameter controlling the choice of suitable attributes and methods for fracture analysis. Data with a small offset-depth ratio from 0.7 to 1.0 may be more suitable for amplitude analysis; whilst the use of travel time or velocity analysis requires a large offset-depth ratio above 1.0, which can help in reducing the effect of the acquisition footprint and structural imprint on the results. Multi-component seismic data is often heavily contaminated with noise, which will limit its application potential in seismic anisotropy analysis. A new method to reduce noise in 3D multi-component seismic data has been developed and has proved to be very helpful in improving data quality. The method can automatically recognize and eliminate strong noise in 3D converted wave seismic data with little interference to useful reflection signals. Component rotation is normally a routine procedure in 3D multi-component seismic analysis. However, this study shows that incorrect rotations may occur for certain acquisition geometry and can lead to errors in shear-wave splitting analysis. A quality control method has been developed to ensure this procedure is correctly carried out. The presence of seismic anisotropy can affect the quality of seismic imaging, but the study has shown that the magnitude of the effects depends on the data type and target depth. The effects of VTI anisotropy (transverse isotropy with a vertical symmetry axis) on P-wave images are much weaker than those on PS-wave images. Anisotropic effects decrease with depth for the P- and PS-waves. The real data example shows that the overall image quality of PS-waves processed by pre-stack time migration has been improved when VTI anisotropy has been taken into account. The improvements are mainly in the upper part of the section. Monitoring fluid distribution is an important task in producing reservoirs. A synthetic study based on a multi-scale rock-physics model shows that it is possible to use seismic anisotropy to derive viscosity information in a HTI medium (transverse isotropy with a horizontal symmetry axis). The numerical modelling demonstrates the effects of fluid viscosity on medium elastic properties and seismic reflectivity, as well as the possibility of using them to discriminate between oil and water saturation. Analysis of real data reveals that it is hard to use the P-wave to discriminate oil-water saturation. However, characteristic shear-wave splitting behaviour due to pore pressure changes demonstrates the potential for discriminating between oil and water saturation in fractured reservoirs.

Download or read book Seismic Signatures and Analysis of Reflection Data in Anisotropic Media written by I. Tsvankin and published by Elsevier. This book was released on 2001-03-02 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following the breakthrough in the last decade in identifying the key parameters for time and depth imaging in anisotropic media and developing practical methodologies for estimating them from seismic data, this title primarily focuses on the far reaching exploration benefits of anisotropic processing. This volume provides the first comprehensive description of reflection seismic signatures and processing methods in anisotropic media. It identifies the key parameters for time and depth imaging in transversely isotropic media and describes practical methodologies for estimating them from seismic data. Also, it contains a thorough discussion of the important issues of uniqueness and stability of seismic velocity analysis in the presence of anisotropy. The book contains a complete description of anisotropic imaging methods, from the theoretical background to algorithms to implementation issues. Numerous applications to synthetic and field data illustrate the improvements achieved by the anisotropic processing and the possibility of using the estimated anisotropic parameters in lithology discrimination.

Download or read book Geophysics and Geosequestration written by Thomas L. Davis and published by Cambridge University Press. This book was released on 2019-05-09 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the geophysical techniques and analysis methods for monitoring subsurface carbon dioxide storage for researchers and industry practitioners.

Download or read book Multicomponent Seismic Technology written by Bob Adrian Hardage and published by . This book was released on 2011 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Multi Component Seismic Data in the Shallow Water Environment of the Arabian Gulf written by Zhao Zhang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The quality of the seismic data is essential to quantitative reservoir characterization of rock properties and geological structure interpretation. Although marine multi-component seismic data hold a wealth of information about both compressional and shear velocities, the acquisition suffers from high levels of noise, which make the processing a challenging task and drastically decreases optimal value extraction. This dissertation employs a four component (4C) processing workflow via advanced time-frequency-wavenumber filtering and polarization methods to improve data quality for further interpretation and reservoir characterization. The proposed workflow is used to enhance seismic reflected energy and explore the shear wave information in the horizontal components. This study makes use of one 2D seismic line and well log dataset from one offshore in the southern Arabian Gulf (Abu Dhabi, United Arab Emirates). A combination of strong lateral seafloor heterogeneities, shallow water depths (~10m), and hard sea bottom results in highly interfering and complex wave-fields and seemingly noisy seismic data acquired in this shallow water environment. Meanwhile, we expect converted wave modes (PS-S waves) due to the strong reflector at hard sea bottom. In this work, we first propose sophisticated filtering algorithms to attenuate surface waves, and then designed advanced processing sequence combined with existing techniques for converted waves detection. Compared to body waves, surface waves are characterized by low velocity, low frequency and high polarization. First, we utilize the variable factor S transform to transform the seismic data from time domain to time-frequency-wavenumber(TFK) domain. This designed transform provides better resolution control on both time and frequency by adjusting the shape of Gaussian window function through additional parameters. Second, we estimate the impacts of residual surface waves on rotation and suppress those waves using TFK dependent polarization analysis. Polarization attributes, ellipticity and rise angle, are calculated through a developed 3D covariance matrix analysis that exploits the joint relationship of wavenumber, time, frequency and polarization. Those computed attributes are used for attenuating the surface waves and determining radial and transverse components. Third, we introduce the new 4C ocean bottom cable (OBC) processing strategy using both compressional and shear waves to recover the image of the subsurface from noisy seismic data. Comparing the time slices and gathers before and after using the strategy, it is observed that the method, described here, attenuates surface waves and remnant surface waves effectively and improves the signal to noise ratio without weakening the desired reflected signals. The results from this dissertation will find application in reservoir characterization from shear wave and converted wave analysis. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155180

Download or read book Isotropic and Anisotropic Seismic Tomography Using Active Source and Earthquake Records written by Yu-Pin Lin and published by Springer. This book was released on 2017-06-16 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents investigations on the Earth's seismic structure using both active-source and natural earthquake records. It discusses the ground-truth data obtained from the TAiwan Integrated GEodynamics Research (TAIGER) active-source experiments that provides excellent and unique insights into the shallow crustal structures beneath Taiwan. It also explores the full-wave sensitivity kernels, which account for the effects of all possible wave interferences involved in shear-wave splitting and therefore loosen the restrictions on source-receiver geometry amenable to shear-wave splitting analysis. Moreover, it describes the 3D Fréchet kernels, which enable us to resolve the vertical and lateral variations in seismic anisotropy and obtain 3D images of the Earth's anisotropic structure, as well as the practice in Southern California that enables us to infer the state of the stress and strain in the lithosphere and the dynamics of the asthenospheric mantle flow for a better understanding of the strength and deformation in the upper mantle beneath the San Andreas Fault system.

Download or read book Plate Deformation from Cradle to Grave written by Andy Nowacki and published by Springer Science & Business Media. This book was released on 2012-12-14 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Earth's rocky mantle convects to lose heat, which comes from the liquid iron core below. The mantle's interfaces - the core-mantle boundary, and the lithosphere - may hold the key to understanding mantle motion because of the seismic anisotropy present in these parts of the Earth. In this thesis, Andy Nowacki presents a precise but comprehensive review of the current state of the art in studying flow with anisotropy, mineral physics and geodynamics. New measurements of shear wave anisotropy in the lowermost mantle and at mid-ocean ridges are used to constrain mechanisms of creep and melt extraction in the mantle. A model of global flow is used to predict anisotropy in the deep Earth, and novel methods to forward model shear wave splitting are described. Future studies of mantle flow must incorporate the understanding gained in this thesis. The thesis contains a substantive introduction to the structure of the Earth, seismic anisotropy in general and in the core-mantle boundary region, and mid-ocean ridge processes. It also describes novel methods for forward modelling and interpreting shear wave splitting data. Three chapters present timely research into dynamics at divergent plate boundaries and at the core-mantle boundary.

Download or read book Analysis of Seismic Anisotropy in 3D Multi component Seismic Data written by Zhongping Qian and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acquisition and interpretation of multi component seismic data in isotropic and azimuthally anisotropic media written by Daniel Andrew Ebrom and published by . This book was released on 1991 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Foundations of Anisotropy for Exploration Seismics written by K. Helbig and published by Elsevier. This book was released on 2015-08-11 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few years, anisotropy has become a "hot topic" in seismic exploration and seismology. It is now recognised that geological media deviate more or less from isotropy. This has consequences for acquisition, processing and interpretation of seismic data and also helps determine the cause of anisotropy and adds to our knowledge concerning the structure of the medium at scales beyond the resolution of the seismic method. This volume addresses the theoretical foundations of wave propagation in anisotropic media at an easily accessible level. The treatment is not restricted to exploration seismology. The book commences with fundamental material and covers the description of wave propagation in anisotropic conditions by means of slowness and wave surfaces. It continues to explore the theory of elasticity, the interaction of elasticity and material symmetry and conditions imposed by the stability of the medium. Wave propagation in general anisotropic solids are discussed referring in particular to singular and longitudinal directions. Slowness and wave surfaces in transversely isotropic media and in the planes of symmetry of orthorhombic media is presented and then moves on to wave propagation in orthorhombic media by means of "squared slowness surfaces". The latter part of the book deals with layer-induced anisotropy showing how a particular internal structure of a medium leads to anisotropy and how much of this structure can be recovered by "inversion" of the modelling algorithm. A few fundamental aspects of exploration seismology are also discussed. The final chapter discusses how concepts which were developed by Kelvin, but only recently understood, can be utilised to determine the symmetry class and orientation of an elastic medium.

Download or read book Seismic Reflection Processing written by S.K. Upadhyay and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic Reflection Processing coherently presents the physical concepts, mathematical details and methodology for optimizing results of reservoir modelling, under conditions of isotropy and anisotropy. The most common form of anisotropy - transverse isotropy - is dealt with in detail. Besides, practical aspects in reservoir engineering - such as interval isotropic or anisotropic properties of layered media; identifying lithology, pore-fluid types and saturation; and determining crack/fracture-orientations and density - form the core of discussions. This book incorporates significant new developments in isotropic and anisotropic reflection processing, while organizing them to improve the interpretation of seismic reflection data and optimizing the modeling of hydrocarbon reservoirs. It is written primarily as a reference and tutorial for graduate/postgraduate students and research workers in geophysics.

Download or read book 3C Seismic and VSP Converted waves and vector wavefield applications written by James Gaiser and published by SEG Books. This book was released on 2016-06-30 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: 3C seismic applications provide enhanced rock property characterization of the reservoir that can complement P-wave methods. Continued interest in converted P- to S-waves (PS-waves) and vertical seismic profiles (VSPs) has resulted in the steady development of advanced vector wavefield techniques. PS-wave images along with VSP data can be used to help P-wave interpretation of structure in gas obscured zones, of elastic and fluid properties for lithology discrimination from S-wave impedance and density inversion in unconventional reservoirs, and of fracture characterization and stress monitoring from S-wave birefringence (splitting) analysis. The book, which accompanies the 2016 SEG Distinguished Instructor Short Course, presents an overview of 3C seismic theory and practical application: from fundamentals of PS-waves and VSPs, through to acquisition and processing including interpretation techniques. The emphasis is on unique aspects of vector wavefields, anisotropy, and the important relationships that unify S-waves and P-waves. Various applications and case studies demonstrate image benefits from PS-waves, elastic properties and fluid discrimination from joint inversion of amplitude variations with offset/angle (AVO/A), and VSP methods for anisotropic velocity model building and improved reservoir imaging. The book will be of interest to geophysicists, geologists, and engineers, especially those involved with or considering the use of AVO/A inversion, fracture/stress characterization analyses, or interpretation in gas-obscured reservoirs.

Download or read book Interpretation of Three dimensional Seismic Data written by Alistair R. Brown and published by American Association of Petroleum Geologists. This book was released on 1999 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi component Seismic Modeling and Robust Pre stack Seismic Waveform Inversion for Elastic Anisotropic Media Parameters written by Tao Li and published by . This book was released on 2016 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Consideration of azimuthal anisotropy, at least to an orthorhombic symmetry is important in exploring the naturally fractured and unconventional hydrocarbon reservoirs. Full waveform inversion of multicomponent seismic data can, in principle, provide more robust estimates of subsurface elastic parameters and density than the inversion of single component (P wave) seismic data. In addition, azimuthally dependent anisotropy can only be resolved by carefully studying the multicomponent seismic displacement data acquired and processed along different azimuths. Such an analysis needs an inversion algorithm capable of simultaneously optimizing multiple objectives, one for each data component along each azimuth. In this dissertation, I propose a novel multiobjective methodology using a parallelized version of NSGA II for waveform inversion of multicomponent seismic data along two azimuths. The proposed methodology is also an improvement of the original NSGA II in overall computational efficiency, preservation of population diversity, and rapid sampling of the model space. Next, the proposed methodology is applied on wide azimuth and multicomponent vertical seismic profile (VSP) data to provide reliable estimation of subsurface anisotropy at and near the well location. Prestack waveform inversion was applied to the wide-azimuth multicomponent VSP data acquired at the Wattenberg Field, located in Denver Basin of northeastern Colorado, USA, to characterize the Niobrara formation for azimuthal anisotropy. By comparing the waveform inversion results with an independent study that used a joint slowness-polarization approach to invert the same data, we conclude that the waveform inversion is a reliable tool for inverting the wide-azimuth multicomponent VSP data for anisotropy estimation. Last but not least, an anisotropic elastic three-dimensional scheme for modeling the elastodynamic wavefield is developed in order to go beyond the 1D layering assumption being used in previous studies. The method uses quadratic tetrahedral elements to discretize the model in space, Newmark family of time integration scheme to discretize in time, and a perfectly matched layer as the absorbing boundary condition. Various preconditioned conjugate gradient approaches were tested and implemented in the algorithm to improve the numerical efficiency of the finite element solver and the entire methodology was optimized to run efficiently in a parallel computing architecture. By computing synthetic seismic responses for a homogeneous medium and for a layered anisotropic medium and comparing results with other analytical and numerical solutions, the validity of the methodology was also verified for numerical accuracy.