Reflection Coefficients And Azimuthal Avo Analysis In Anisotropic Media

Observing offset-dependent seismic reflectivity has proven to be a valuable exploration tool for the direct detection of hydrocarbons. This monograph provides a comprehensive review of reflection coefficients and their approximations in isotropic media, followed by an in-depth discussion of reflection amplitudes in anisotropic media. No prior knowledge of seismic anisotropy is assumed, and considerable effort is spent to introduce wave propagation and medium parameterizations useful for surface seismic applications in the presence of anisotropy. The first anisotropic model discussed is transverse isotropy with a vertical axis of symmetry (VTI media), typically used to describe shale sequences. Then the study of VTI reflection coefficients is extended to transverse isotropy with a horizontal axis of symmetry (HTI) - the symmetry system that describes a system of parallel vertical cracks. Analysis of the "Shuey-type" approximate HTI P-wave reflection coefficient makes it possible to devise fracture-detection algorithms based on the inversion of azimuthal differences of the P-wave AVO gradient. The monograph also presents analysis of shear- and converted-wave reflection coefficients for HTI and orthorhombic models, discusses practical aspects of applying the azimuthal AVO analysis, and mentions promising recent results.

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, Seismic Signatures and Analysis of Reflection Data in Anisotropic Media 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. Focuses on the far reaching exploration benefits of anisotropic processing First comprehensive description of reflection seismic signatures and processing methods in anisotropic media

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.

Presents an analysis of seismic signatures for azimuthally anisotropic media and shows anisotropic inversion/processing methods for wide-azimuth reflection data and VSP surveys. The focus is kinematic parameter-estimation techniques; the prestack amplitudes section includes AVO and attenuation coefficients; field examples are included.

This special issue contains contributions presented at the international workshop Seismic Waves in Laterally Inhomogeneous Media V, which was held at the Castle of Zahrádky, Czech Republic, June 5 - 9, 2000. The workshop, which was attended by about 60 seismologists from 16 countries, was devoted mainly to the current state of theoretical and computational means of study of seismic wave propagation in complex structures. The special issue begins with papers dealing with the study and the application of the ray methods. Problems such as coupling of quasi-shear waves or smoothing of models for effective ray computations are dealt with. Applications of the ray methods in seismic exploration are presented. Further, directional wavefield decomposition, phase space, path integral and parabolic equation methods are discussed. Attention is also devoted to attenuation and scattering problems, and to seismic inversion problems.

All rock masses are seismically anisotropic, but we generally ignore this in our seismic acquisition, processing, and interpretation. The anisotropy nonetheless does affect our data, in ways that limit the effectiveness with which we can use it, as long as we ignore it. This book, produced for use with the fifth SEG/EAGE Distinguished Instructor Short Course, helps us understand why this inconsistency between reality and practice has been so successful in the past and why it will be less successful in the future as we acquire better seismic data (especially including vector seismic data) and correspondingly higher expectations of it. This book helps us understand how we can modify our practice to more fully realize the potential inherent in our data through algorithms which recognize the fact of seismic anisotropy.

This detailed book systematically investigates subsurface geological fractures using rock mechanics, geology, and geophysics. Based on geological fracture mechanisms and fracture boundary conditions, it presents new finite-difference equations for the simulation of seismic wave responses to geological fractures, and proposes innovative AVO inversion equations for the accurate estimation of the rock properties of the fractured medium. It employs schematics, snapshots, color images and charts to demonstrate the mechanical characteristics of the fractures, the seismic wave-field response to the fractures, the seismic data attributes of the fractures and the rock properties of the fractures obtained via inversion. It provides a new methodology for enhancing geological fracture detection technology and for the accurate delineation of fractured reservoirs that ultimately benefits reservoir and mining engineers, geologists and geophysicists in terms of optimizing reservoir recovery, well performance and mining safety.

This book focuses on essential theories, methods and techniques in the field of environmental and engineering geophysics that can contribute to resource detection and environmental protection. Geophysics has been playing an important role in exploring the earth, locating vital resources and promoting the development of society. This book covers a range of topics including the exploration of modern resources, such as ore deposits, coal mines, shale gas and geothermal power, and the monitoring of geological disasters, including the rock-soil body, ground deformation, mines, specific rock-soil engineering disasters, desertification of land and environmental abnormalities. This book not only offers a valuable resource for geophysical researchers; it also demonstrates how geophysics theories and methods can be practically implemented to protect our environment and promote the development of human society.