Geophysical Signal Processing

Addresses the construction, analysis, and interpretation of mathematical and statistical models. The practical use of the concepts and techniques developed is illustrated by numerous applications. The chosen examples will interest many readers, including those engaged in digital signal analysis in disciplines other than geophysics.

Written for students as well as professionals who work with and support geophysicists, this book presents a simple and informal discussion of fundamental concepts which underlie the quantitative part of geophysical analysis and interpretation. These general concepts are applicable for an analytical approach to any phenomena that can be measured and recorded. With examples and figures created using Microsoft Excel®, this book is accessible and insightful. Topics covered include: the concept of signals based on the sine function; the summation of sine waves as a more complicated signal; the notion of Fourier series and the spectral representation of signals; digital sampling and discrete representation of signals; the discrete Fourier transform and inverse transform; the concept of filtering in the spectral domain; and the idea of filtering outside of the spectral domain, by convolution, and the relationship between the measurement and spectral domains. This book will be valuable for geologists, junior seismic interpreters, software developers, high school and university students, and geophysical professionals seeking a refresher of the basic concepts.

Concise, self-contained survey of data processing methods in geophysics and other sciences, for upper level science and engineering students.

This updated translation connects the literature and routine activities of geophysicists. It shows how practical problems have links to seismic data analysis theory. Phase and amplitude distortions to the seismic signal, the physical processes that it undergoes, and the interpretation methods to recover rock physics properties are explained. Filling the gap between theoretical literature and the routine activities of geophysicists in the oil industry, The Seismic Signal and Its Meaning is a translation of the second edition of Análise do Sinal Sísmico, published in Portuguese by Sociedade Brasileira de Geofísica (SBGf). For those performing acquisition, processing, and/or interpretation, this book will aid an understanding of how practical problems may have important links to seismic data analysis theory. With an emphasis on providing an objective description of the physical and mathematical aspects that support these links, the rules necessary for robust reservoir characterization are presented. With an extensive development of Gassmann’s (and Biot) theory, the book concentrates on phase and amplitude distortions to the seismic signal, the physical processes that it undergoes, and the interpretation methods to recover rock physics properties. Capturing 30 years of teaching and improvement as a part of Petrobras’ internal courses, the book is a modern treatment, reflecting the many advances that have occurred in geophysics. The book serves as both a text and a reference.

Presents an advanced overview of Digital Signal Processing and its applications to exploration seismology, for electrical engineers, geophysicists and petroleum professionals.

When some useful information is hidden behind a mass of unwanted information we often resort to information processing used in its broad sense or specifically to signal processing when the useful information is a waveform. In geophysical surveys, in particular in aeromagnetic and gravity surveys, from the measured field it is often difficult to say much about any one specific target unless it is close to the surface and well isolated from the rest. The digital signal processing approach would enable us to bring out the underlying model of the source, that is, the geological structure. Some of the tools of dsp such as digital filtering, spectrum estimation, inversion, etc., have found extensive applications in aeromagnetic and gravity map analysis. There are other emerging applications of dsp in the area of inverse filtering, three dimensional visualization, etc. The purpose of this book is to bring numerous tools of dsp to the geophysical community, in particular, to those who are entering the geophysical profession. Also the practicing geophysicists, involved in the aeromagnetic and gravity data analysis, using the commercially available software packages, will find this book useful in answering their questions on "why and how?". It is hoped that such a background would enable the practising geophysicists to appreciate the prospects and limitations of the dsp in extracting useful information from the potential field maps. The topics covered are: potential field signals and models, digital filtering in two dimensions, spectrum estimation and application, parameter estimation with error bounds.

Covering ideas and methods while concentrating on fundamentals, this book includes wave motion; digital imaging; digital filtering; visualization aspects of the seismic reflection method; sampling theory; the frequency spectrum; synthetic seismograms; wavelet processing; deconvolution; seismic attributes; phase rotation; and seismic attenuation.