Share Email Print

Proceedings Paper

Joint imaging with primary reflections and deep water multiples
Author(s): Edmund C. Reiter; M. Nafi Toksoz
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

A ray equation based Kirchhoff depth migration is used to image primary reflections and deep water multiples recorded on an ocean bottom hydrophone (OBH). The resulting image of the subbottom sediments is shown to be improved by inclusion of the deep water multiple in the imaging process. Field data acquired jointly by Woods Hole Oceanographic Institute and University of Texas Institute for Geophysics at Austin consisting of an OBH (2300 m depth) recording a 10,800 cubic inch airgun array, are used to illustrate the feasibility of this technique. Images are obtained from both the primary reflections and energy which has undergone an additional path through the water column. Comparison of these images reveal an excellent correlation of reflectors with the predicted polarity reversal observed in the multiple's image. Synthetic data are used to examine the difficulties in identifying the true path of the water column multiple. For flat layered media there are two different multiple paths, one which reflects beneath the source and one which reflects over the receiver, which have identical travel times when the seafloor is approximately horizontal. They do not however have the same amplitude and it can be shown that their amplitudes differ sufficiently to allow a reliable image to be extracted from the energy which reflects over the receiver (receiver multiple). The difference in amplitude between this receiver multiple and the primary reflection is mostly due to geometric spreading and attenuation in the water column. This is usually small enough to allow observation of most primary events in the receiver multiple. While conventional seismic imaging techniques utilize only primary reflected energy we have shown that for an on bottom recording geometry energy reflecting from the free surface may also be used to image the subsurface. As a final step the image obtained from the multiple is corrected for the r phase shift from the free surface and added to the image from the primary reflection. The final image shows both extended lateral coverage and increased signal to noise.

Paper Details

Date Published: 1 November 1990
PDF: 9 pages
Proc. SPIE 1301, Digital Image Processing and Visual Communications Technologies in the Earth and Atmospheric Sciences, (1 November 1990); doi: 10.1117/12.21418
Show Author Affiliations
Edmund C. Reiter, Massachusetts Institute of Technology (United States)
M. Nafi Toksoz, Massachusetts Institute of Technology (United States)

Published in SPIE Proceedings Vol. 1301:
Digital Image Processing and Visual Communications Technologies in the Earth and Atmospheric Sciences
Paul Janota, Editor(s)

© SPIE. Terms of Use
Back to Top