Processing and Analysis
Published:January 01, 2016
In Chapter 5, processing and analysis methods are provided in detail for PS-waves in terms of key processing stages. Unique for 3C seismic data are rotation of coordinate axes, statics computation, S-wave splitting analysis, polarization filters, and vector fidelity compensation. In terms of transformation to zero offset, vertical VP/VS (? 0) for registration, common-conversion-point (CCP) gathering, and converted-wave NMO are emphasized. Other important basic processing steps are also reviewed: deconvolution, dual-sensor summation, and elastic wavefield decomposition. In terms of VSP data, conventional processing and wavefield separation are reviewed, and advanced anisotropy analyses are highlighted.
Figures & Tables
3C Seismic and VSP: Converted waves and vector wavefield applications
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.