HUANG Jian-Ping,
YANG Ji-Dong,
LI Zhen-Chun et al
.2016.An amplitude-preserved Gaussian beam migration based on wave field approximation in effective vicinity under irregular topographical conditions.Chinese Journal Of Geophysics,59(6): 2245-2256,doi: 10.6038/cjg20160627
An amplitude-preserved Gaussian beam migration based on wave field approximation in effective vicinity under irregular topographical conditions
HUANG Jian-Ping1, YANG Ji-Dong1, LI Zhen-Chun1, LI Hui-Feng2
1. Department of Geophysics, China University of Petroleum (East China), Qingdao 266580, China; 2. Department of Geophysics, Xi'an Shiyou University, Xi'an 710065, China
Abstract：With the transformation of seismic exploration to regions with irregular topography areas in China, it is of vital importance for seismic processing, interpretation and subsequent seismic attribute analysis, reservoir prediction to develop a seismic migration method which is highly accurate and strongly robust. Based on the theory of wave field approximation in effective vicinity, we developed a more accurate method of pre-stack amplitude-preserved Gaussian beam migration, which is adaptable for irregular topographical conditions. On the basis of conventional Gaussian beam migration from horizontal surface and according to the approximate wave field expressed by Gaussian beam in the effective vicinity of central ray, we derived an amplitude-preserved Gaussian beam migration formula under irregular topographical conditions, and proposed a more accurate computation method for propagation angle of paraxial ray. Compared with existing methods for Gaussian beam migration, the proposed method in this paper not only considers the linear effects of irregular topography on travel time, but also first introduces the items of quadratic travel time correction and amplitude correction caused by the irregular topography and the variation in near-surface velocity, leading to more valid and accurate migration results than the previous methods. Two typical numerical examples verify the validity of the proposed method.
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