Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house.
— Henri Poincare (1854-1912)
The preceding chapters have explored frequency-dependent phenomena related to acquisition (vibroseis harmonics) and wave propagation (shallow-water waveguide, layer-induced anisotropy, and attenuation) that would be seen and dealt with on prestack data. Data processing ideally will remove or correct for those phenomena and will be unseen by the interpreter. However, dispersion (in our broad meaning) remains in the poststack realm of the final imaged data. In the sections below, we consider the frequency behavior of thin-bed response set up by two neighboring reflections, the more general interference from many reflections, and finally the special case of reflection from a gradational boundary.
Figures & Tables
Elements of Seismic Dispersion: A Somewhat Practical Guide to Frequency-dependent Phenomena (SEG Distinguished Instructor Series No. 15) covers selected effects encountered in the acquisition, processing, and interpretation of reflectionseismic data. The material, based on the 2012 SEG Distinguished Instructor Short Course, shows how those phenomena arise, how they can be characterized, and the important information they contain. The text shows how spectral decomposition and time-frequency methods have led to improved understanding and use of nonlinear harmonics, near-surface guided waves, layer-induced anisotropy, velocity dispersion and attenuation, interference, and Biot reflection. Accessible discussion is augmented by examples, figures, and references to primary literature for further study. This book will interest technical managers and those who work in acquisition, processing, and interpretation of seismic data. (DISC on DVD, 761A, is also available.)