Seismic True Amplitude Imaging

Providing a pictorial presentation of the basic principles of Kirchhoff-type imaging and proceeding to a comprehensive treatment of its kinematic and dynamic aspects, this book is a valuable addition for anyone interested in the theory and practices of seismic data processing for imaging and parameter estimation with all its attendant processes.

An important task in seismic reflection imaging is to estimate subsurface structures from the prestack data. This means that the reflection events in the recorded data have to be transformed into images in the depth domain, the reflectors. A geometrically appealing approach for the corresponding process is Kirchhoff migration which is based on an integral solution of the wave equation. Applied in its original purely kinematic form, this process provides a structural image of the target region under investigation. However, Kirchhoff migration is also able to handle the amplitude-related aspects of wave propagation, thus allowing to assign physically sound amplitude values to reflector images. In such a true-amplitude migration, the geometrical spreading effects are removed from the input data during the imaging process and, thus, reflector amplitudes become basically a measure of the angle-dependent reflection coefficient. Commencing with the basics of wave propagation and ray theory, a complete description of Kirchhoff migration is presented. By relating the strict mathematical derivation of true-amplitude Kirchhoff migration to clear geometrical concepts, the gap between the originally graphical migration schemes and the nowadays available analytical descriptions based on a stationary-phase evaluation is closed. Further aspects relevant to the correct recovery of amplitudes in depth migration, such as the handling of topography and irregular geometries, are explained in a mathematical as well as in a geometrical manner. Finally, Kirchhoff migration is integrated into a seismic reflection imaging workflow based on the data-driven common-reflection-surface (CRS) stack method.

Extracting information from seismic data requires knowledge of seismic wave propagation and reflection. The commonly used method involves solving linearly for a reflectivity at every point within the Earth, but this book follows an alternative approach which invokes inverse scattering theory. By developing the theory of seismic imaging from basic principles, the authors relate the different models of seismic propagation, reflection and imaging - thus providing links to reflectivity-based imaging on the one hand and to nonlinear seismic inversion on the other. The comprehensive and physically complete linear imaging foundation developed presents new results at the leading edge of seismic processing for target location and identification. This book serves as a fundamental guide to seismic imaging principles and algorithms and their foundation in inverse scattering theory, and is a valuable resource for working geoscientists, scientific programmers and theoretical physicists.

Accompanying CD-ROM includes PDF slides for teaching the material in the book and the C3-narrow-azimuth classic data set.

This is the first book of its kind on seismic amplitude inversion in the context of reflection tomography. The aim of the monograph is to advocate the use of ray-amplitude data, separately or jointly with traveltime data, in reflection seismic tomography. The emphasis of seismic exploration is on imaging techniques, so that seismic section can be interpreted directly as a geological section. In contrast it is perhaps ironic that, in decades of industrial seismology, one major aspect of waveform data that potentially is easier to measure and analyse has generally been ignored. That is, the information content of seismic amplitudes. Perhaps the potential complexity has deterred most researchers from a more thorough investigation of the practical use of seismic amplitude data. The author of this volume presents an authoritative and detailed study of amplitude data, as used in conjunction with traveltime data, to provide better constraints on the variation of seismic wave speed in the subsurface. One of the fundamental problems in conventional reflection seismic tomography using only traveltime data is the possible ambiguity between the velocity variation and the reflector depth. The inclusion of amplitude data in the inversion may help to resolve this problem because the amplitudes and traveltimes are sensitive to different features of the subsurface model, and thereby provide more accurate information about the subsurface structure and the velocity distribution. An essential goal of this monograph is to make the amplitude inversion method work with real reflection seismic data.

Seismic Exploration of Hydrocarbons in Heterogeneous Reservoirs: New Theories, Methods and Applications is based on the field research conducted over the past decade by an authoring team of five of the world’s leading geoscientists. In recent years, the exploration targets of world's oil companies have become more complex. The direct detection of hydrocarbons based on seismic wave data in heterogeneous oil/gas reservoirs has become a hot spot in the research of applied and exploration geophysics. The relevant theories, approaches and applications, which the authors have worked on for years and have established mature technical processes for industrial application, are of significant meaning to the further study and practice of engineers, researchers and students in related area. Authored by a team of geophysicists in industry and academia with a range of field, instruction, and research experience in hydrocarbon exploration Nearly 200 figures, photographs, and illustrations aid in the understanding of the fundamental concepts and techniques Presents the latest research in wave propagation theory, unconventional resources, experimental study, multi-component seismic processing and imaging, rock physics modeling and quantitative seismic interpretation Sophisticated approach to research systematically forms an industrial work flow for geoscience and engineering practice

Seismic imaging methods are currently used to produce images of the Earth's subsurface properties at diverse length scales, from high-resolution, near-surface environmental studies for oil and gas exploration to long-period images of the entire planet. This book presents the physical and mathematical basis of imaging algorithms in the context of controlled-source reflection seismology. The approach taken is motivated by physical optics and theoretical seismology. The theory is constantly put into practice via a graded sequence of computer exercises using the widely available SU (Seismic Unix) software package.

Our proposed work on high resolution/high fidelity seismic imaging focused on three general areas: (1) development of new, more efficient, wave-equation-based propagators and imaging conditions, (2) developments towards amplitude-preserving imaging in the local angle domain, in particular, imaging methods that allow us to estimate the reflection as a function of angle at a layer boundary, and (3) studies of wave inversion for local parameter estimation. In this report we summarize the results and progress we made during the project period. The report is divided into three parts, totaling 10 chapters. The first part is on resolution analysis and its relation to directional illumination analysis. The second part, which is composed of 6 chapters, is on the main theme of our work, the true-reflection imaging. True-reflection imaging is an advanced imaging technology which aims at keeping the image amplitude proportional to the reflection strength of the local reflectors or to obtain the reflection coefficient as function of reflection-angle. There are many factors which may influence the image amplitude, such as geometrical spreading, transmission loss, path absorption, acquisition aperture effect, etc. However, we can group these into two categories: one is the propagator effect (geometric spreading, path losses); the other is the acquisition-aperture effect. We have made significant progress in both categories. We studied the effects of different terms in the true-amplitude one-way propagators, especially the terms including lateral velocity variation of the medium. We also demonstrate the improvements by optimizing the expansion coefficients in different terms. Our research also includes directional illumination analysis for both the one-way propagators and full-wave propagators. We developed the fast acquisition-aperture correction method in the local angle-domain, which is an important element in the true-reflection imaging. Other developments include the super-wide angle one-way propagator and special full-wave reverse-time migration method. Finally, we studied the theoretical basis of true-reflection imaging and bridges imaging and inversion with the theory of diffraction tomography.

This book presents a comprehensive overview of relative fidelity preservation processing methods and their applications within the oil and gas sector. Four key principles for wide-frequency relative fidelity preservation processing are illustrated throughout the text. Seismic broadband acquisition is the basis for relative fidelity preservation processing and the influence of seismic acquisition on data processing is also analyzed. The methods and principles of Kirchhoff integral migration, one-way wave equation migration and reverse time migration are also introduced and illustrated clearly. Current research of relative amplitude preservation migration algorithms is introduced, and the corresponding numerical results are also shown. RTM (reverse time migration) imaging methods based on GPU/CPU systems for complicated structures are represented. This includes GPU/CPU high performance calculations and its application to seismic exploration, two-way wave extrapolation operator and boundary conditions, imaging conditions and low frequency noise attenuation, and GPU/CPU system based RTM imaging algorithms. Migration velocity model building methods in depth domain for complicated structures are illustrated in this book. The research status and development of velocity model building are introduced. And the impacting factors are also discussed. Several different velocity model building methods are also represented and analyzed. The book also provides the reader with several case studies of field seismic data imaging in different kinds of basins to show the methods used in practice.