Theory of large-step wavefield depth extrapolation

	Theory of large-step wavefield depth extrapolation
	Liu Hong; Yuan Jiang-Hua; Chen Jing-Bo; Shou Hao; Li You-Ming
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2006-11-01
卷号	49 期号:6 页码:1779-1793
关键词	large-step-wavefield depth extrapolation time migration depth migration exponent transform Lie algebraic integral pseudo-differential operator
ISSN号	0001-5733
文献子类	Article
英文摘要	Wavefield extrapolation is the foundation of seismic migration imaging. Finding a way of quick and object oriented wavefield extrapolation is significant not only for deep seismic exploration but also for imaging with super-tremendous seismic data acquired from non-combination receivers, both highly needed to develop in petroleum prospecting. To image target zones, as far as all present wavefield extrapolation methods are concerned; including travel-time based Dix-formula methods, ray tracing, small-step depth recursion, etc., the adaptability to complex media, precision and computing efficiency are not satisfying for practical needs in some respects. In this paper, a new technique (so-called large-step wavefield depth extrapolation method), that is based on the Le algebraic integral of operator's phase to compute depth extrapolation operator efficiently, is proposed. In the method, the complex phase of object oriented wavefield extrapolation operator's symbol is expressed as a linear combination of wavenumbers, and the coefficients of linear combination are all in the form of the integral of interval velocity functions and their derivatives over depth. Moreover, the computation is convenient and needs less storage space. With phase shift plus correction, the wavefield extrapolation operator is implemented using FFF (Fast Fourier Transform) in spatial and wavenumber domains. Here, the kinetic equivalent relationship is resorted to derive the expression convenient for computation. We compare the precision of one-step scheme with that of two-step scheme for expanding an operator's primary symbol function, which illustrates the large-step scheme is more accurate than its recursive counterpart. Besides, in a linearly variant medium laterally and vertically, the point source pulse response of the large-step method is compared with that of depth recursion methods. The numerical examples indicate that travel-time precision of the large-step extrapolation operator mainly depends on the lateral velocity variation modification items in phase shift operator. In addition, in different approximation cases, the dispersion caused by the large-step operator is rather small.
WOS关键词	FINITE-DIFFERENCE MIGRATION ; ONE-WAY ; SYMPLECTIC ALGORITHM ; INHOMOGENEOUS-MEDIA ; PROPAGATION ; MATRIX ; CONTINUATION ; EXPANSION ; SCREEN
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000242388600026
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/66309]
专题	中国科学院地质与地球物理研究所
通讯作者	Liu Hong
作者单位	Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Liu Hong,Yuan Jiang-Hua,Chen Jing-Bo,et al. Theory of large-step wavefield depth extrapolation[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2006,49(6):1779-1793.
APA	Liu Hong,Yuan Jiang-Hua,Chen Jing-Bo,Shou Hao,&Li You-Ming.(2006).Theory of large-step wavefield depth extrapolation.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,49(6),1779-1793.
MLA	Liu Hong,et al."Theory of large-step wavefield depth extrapolation".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 49.6(2006):1779-1793.