Wang - Relative fidelity processing of seismic data: methods and applications

1. Chapter 02

1. Chapter 01
2. Chapter 02
3. Chapter 03
4. Chapter 04
5. Chapter 05

Xiwen Wang

March 2017

Shouwei Zhou and Fujie Sun

January 2016

Edited by Xiwen Wang et al

Petrochina
Lanzhou, Gansu
China

This edition first published 2017
2017 John Wiley & Sons Ltd

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Library of Congress CataloginginPublication Data

Names: Wang, Xiwen, 1956
Title: Relative fidelity processing of seismic data : methods and applications / Professor Xiwen Wang, Petrochina, Lanzhou, Gansu [Province], CH [China].
Description: 1 edition. | Hoboken, NJ : John Wiley & Sons, Inc., 2017. | Series: Wiley series in petroleum industry press | Includes bibliographical references and index.
Identifiers: LCCN 2016049496 (print) | LCCN 2016049872 (ebook) | ISBN 9781119052906 (cloth) | ISBN 9781119052937 (pdf) | ISBN 9781119052920 (epub)
Subjects: LCSH: Seismic prospecting. | PetroleumProspecting. | PetroleumGeology. | Petrology.
Classification: LCC TN271.P4 W344 2017 (print) | LCC TN271.P4 (ebook) | DDC 622/.1592dc23
LC record available at https://lccn.loc.gov/2016049496

Cover Design: Wiley
Cover Image: Jackie2k/Gettyimages

In recent years, lithology reservoir has gradually become the major field of reservoir gain in China. The lithology analysis poses high requirements for amplitude preservation of seismic migration results, but the previous prestack depth migration methods mainly focus on structural imaging. Therefore, much study has been carried out in terms of the amplitude preservation prestack depth migration method using geophysics. Meanwhile, the reservoir of lithology formation is under the control of multiple factors, such as regional structures and depositional facies belts. It presents great exploration difficulties due to being complicated and concealed. On seismic profile, the display reliability of response to lithology formation is subject to the fidelity of processing.

Currently, it is difficult to realize absolute seismic fidelity preservation processing, but relative fidelity preservation processing is possible, which poses higher requirements for seismic data processing, requiring amplitude preservation. It needs to avoid adopting the module that will damage the amplitude relationship of neighboring seismic channels in the processing procedure. In view of the seismic processing problem of lithology reservoir exploration, the relative fidelity preservation processing method that is represented in this book has four critical principles for widefrequency relative fidelity preservation processing: (1) Protection of effective band. The widening of effective band should be based on SNR of data, highfrequency widening and be conducted for the low SNR seismic data; the bandwidth and dominant frequency of deconvolution operator should be controlled. The main effect of deconvolution will be the elevation of energy of highfrequency component within the effective band, to avoid the occurrence of serious notching in the highfrequency end of effective band. (2) Protection of low frequency, especially that of 3~8Hz. The scenarios of low frequency information suppressed due to high resolution, high SNR processing or significant loss of low frequency end effective information with adoption of strong jk denoising, should be avoided. (3) Amplitude preservation. Modification module such as RNA should not be applied, to avoid damaging the lateral relationship of seismic channel amplitude. (4) Phase preservation. The module that will damage phase position should be avoided during processing. Zero phase deconvolution and surface consistent deconvolution will not damage relationship of phases. Compared with highresolution high SNR processed profile, relative fidelity preservation processed profile could reflect seismic response of subsurface sand reservoir quite genuinely. While there is discussion on the processing method of relative fidelity preservation processing or highresolution high SNR, the impact on seismic processing by acquisition mode of seismic data is also elaborated in this book. Seismic broadband acquisition is the basis for relative fidelity preservation processing. Based on profile reflection traits and spectrum characteristics, the impact on the data processed with highresolution, high SNR method or data processed with relative fidelity preservation method by means of seismic acquisition source and observation approach is also analyzed and discussed.

In the previous seismic exploration, in order to satisfy the requirements of structural interpretation, SNR was given much more attention for seismic data imaging and the consideration of fidelity and amplitude preservation of data was insufficient. Nowadays, with the promotion of oil and gas exploration, the requirement for fidelity of seismic data processing is much higher. In recent years, the author has done much in this respect and the research idea and methodology for fidelity preservation imaging have gradually been developed.

The study of the relative fidelity preservation processing method, elaborates the method and principle of the Kirchhoff integral migration method based on ray theory, the oneway wave equation migration based on wavefield extrapolation and twoway wave equation reverse time migration. Meanwhile, the study status of respective amplitude preservation migration algorithm is introduced. The methods of critical technology, including reverse time migration imaging based on a GPU/CPU system for complicated structures and depth domain velocity modeling for complicated structural zone, are represented. Also, the pertinent fidelity preservation imaging processing measures and application performance are applied in practice for different fields, including subsalt imaging of 3D prestack reverse time migration, highdensity, allround seismic data processing for carbonate region, seismic imaging for complicated structures in the Tuha and Jiuquan Basins, and seismic prestack imaging of buried hill structural zone in the Nanpu of Jidong Oilfield. In view of the technical difficulties of seismic imaging and structural interpretation existing in these regions, indepth study on seismic prestack imaging and integrated interpretation has been carried out, with the formation of a pertinent technical series for seismic prestack imaging.