Elastic full waveform inversion of multi-component ocean-bottom cable seismic data: Application to Alba Field, UK North Sea

Sears, T. J. and Barton, P. J. and Singh, S. C. (2010) Elastic full waveform inversion of multi-component ocean-bottom cable seismic data: Application to Alba Field, UK North Sea. Geophysics, 75. R109-R119. ISSN Online ISSN: 1942-2156 Print ISSN: 0016-8033 DOI 10.1190/1.3484097

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Abstract

Elastic full waveform inversion of multichannel seismic data represents a data-driven form of analysis leading to direct quantification of the subsurface elastic parameters in the depth domain. Previous studies have focused on marine streamer data using acoustic or elastic inversion schemes for the inversion of P-wave data. In this paper, P- and S-wave velocities are inverted for using wide-angle multicomponent ocean-bottom cable (OBC) seismic data. Inversion is undertaken using a two-dimensional elastic algorithm operating in the time domain, which allows accurate modeling and inversion of the full elastic wavefield, including P- and mode-converted PS-waves and their respective amplitude variation with offset (AVO) responses. Results are presented from the application of this technique to an OBC seismic data set from the Alba Field, North Sea. After building an initial velocity model and extracting a seismic wavelet, the data are inverted instages. In the first stage, the intermediate wavelength P-wave velocity structure is recovered from the wide-angle data and then the short-scale detail from near-offset data using P-wave data on the Formula (vertical geophone) component. In the second stage, intermediate wavelengths of S-wave velocity are inverted for, which exploits the information captured in the P-wave's elastic AVO response. In the third stage, the earlier models are built on to invert mode-converted PS-wave events on the Formula (horizontal geophone) component for S-wave velocity, targeting first shallow and then deeper structure. Inversion of Formula alone has been able to delineate the Alba Field in P- and S-wave velocity, with the main field and outlier sands visible on the 2D results. Inversion of PS-wave data has demonstrated the potential of using converted waves to resolve shorter wavelength detail. Even at the low frequencies Formula inverted here, improved spatial resolution was obtained by inverting S-wave data compared with P-wave data inversion results.

Item Type: Article
Uncontrolled Keywords: 2010AREP; IA60;
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Geophysics
Volume: 75
Page Range: R109-R119
Identification Number: 10.1190/1.3484097
Depositing User: Sarah Humbert
Date Deposited: 26 Apr 2010 10:22
Last Modified: 23 Jul 2013 09:57
URI: http://eprints.esc.cam.ac.uk/id/eprint/1384

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