The Wave‐Equation 3‐D Prestack Depth Migration of SEG/EAGE Salt and Overthrust Model

Liu, Li-Nong; Liu, Hong; Li, Youming

doi:10.1002/cjg2.491

Cited by 4 publications

(4 citation statements)

References 19 publications

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“…FFD (Fourier Finite Difference [25,26] ), and explicit scheme methods, e.g. generalized screen [29,30] , paves the way for the realization of large-step exponential transform. The shortcoming of depth recursion wavefield extrapolation methods (both implicit and explicit schemes) is that operator error is accumulative.…”

Section: Wavefield Depth Extrapolation With Small-step Recursionmentioning

confidence: 99%

Theory of Large-Step Wavefield Depth Extrapolation

Liu¹,

Yuan²,

Shou³

et al. 2006

Chinese J. Geophys.

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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, we propose a new technique (so‐called large‐step wavefield depth extrapolation method), that is based on the Lie algebraic integral of operator's phase to compute depth extrapolation operator efficiently. 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 FFT (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.

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Section: Wavefield Depth Extrapolation With Small-step Recursionmentioning

confidence: 99%

Theory of Large-Step Wavefield Depth Extrapolation

Liu¹,

Yuan²,

Shou³

et al. 2006

Chinese J. Geophys.

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“…In order to the test migration effect in medium of lateral velocity variation, the migration method of optimal separable approximation is used to compute impulse response with lateral velocity variation. The parameters of model tested are as follows: the number of horizontal space samples is 501 and sample interval is 10m, the number of vertical space samples is 500 and sample interval is 5m, the main frequency of Ricker wavelet is 15Hz and the wavelet is located at 0.9s, the time sample interval is 0.004s [14,15] . Figure 3a shows the wedge velocity model.…”

Section: Impulse Responsementioning

confidence: 99%

Implement of Optimal Separable Approximation in Seismic Migration

Zhang¹,

Liu²,

Li³

2005

Chinese J. Geophys.

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An optimal separable approximation (OSA) is used for characteristic function of one‐way wave operator in the seismic migration algorithm. The characteristic function is expressed as products of functions in space variable (g) and functions in wave number variable (k). Based on optimal separable approximation, the mixed domain algorithm in Fourier and inverse Fourier is presented to approximate one‐way wave operator. To overcome numerical instability from approximating characteristics function near the singular point, an equivalent sticking skill is adopted to improve algorithmic stability. Moreover, separate frequency computation and linear interpolation for space variables are used to improve precision and save time. The impulse response of oneway wave operator on simple and complex lateral variable velocity model shows that the optimal separable approximation can apply to lateral velocity variation in small step. Results on Marmousi model test show the new method can also be used to image complex structure.

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“…In 1988 Franch oil institute built a 2D seismic data volume according to the real geology condition of western Africa Angola [1] . The other one is a 3D salt dome model seismic data volume which was built by America SEG/EAEG according to the geology condition of Mexico Gulf Sigsbee region in the late1990s [2] [3] . So far there hasn't any intact 3D seismic data volume basing on real geology materials in China.…”

Section: Introductionmentioning

confidence: 99%

The algorithm flow of generating 3D seismic data volume in Tarim area by using acoustic equation

Liu

Wang

2011

2011 4th International Congress on Image and Signal Processing

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According to the real geology background of Tarim foreland basin we build 3D seismic data volume of Tarim area by using 3D arbitrary difference precise integration (ADPI) algorithm. It is very beneficial for the processing and explanation of 3D seismic material of Tarim area. Compared with conventional differential method, the 3D ADPI algorithm greatly improves the precision by using local integral semi-analytical method in time domain to get the recursion operator of wave equations. And we adopt stable factor constraints, thus the stability of calculation gets much better. By using an improved adaptive absorbing boundary and the parallelization of serial program, the time consuming of 3D forward modeling is greatly reduced. In the research we gathered 300 shots' Omni-directional seismic data volume. The whole data volume approximates 2T. Compare the geology model with actual seismic records we find 3D ADPI forward modeling can accurately show the structure and layers information of geology model. In complex region it can describe geology structure and seismic physical parameters such as amplitude, frequency, phase and so on.

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The Wave‐Equation 3‐D Prestack Depth Migration of SEG/EAGE Salt and Overthrust Model

Cited by 4 publications

References 19 publications

Theory of Large-Step Wavefield Depth Extrapolation

Theory of Large-Step Wavefield Depth Extrapolation

Implement of Optimal Separable Approximation in Seismic Migration

The algorithm flow of generating 3D seismic data volume in Tarim area by using acoustic equation

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