基于SVD的小尺度地质体地震绕射波成像  

Seismic imaging of small-scale geological body using diffraction wave based on SVD algorithm

作　　者：徐军 刘斌[1,2] 赵庆献 XU Jun;LIU Bin;ZHAO Qing-Xian(Key Laboratory of Marine Mineral Resource,Ministry of Natural Resource,Guangzhou 510760,China;Guangzhou Marine Geological Survey,Guangzhou 510760,China)

机构地区：[1]自然资源部海底矿产资源重点实验室,广东广州510760 [2]广州海洋地质调查局,广东广州510760

出　　处：《物探与化探》2019年第5期1074-1082,共9页Geophysical and Geochemical Exploration

基　　金：国家自然科学青年基金项目(41604110);国家重点研发计划项目(2017YFC0307406)

摘　　要：充分利用小尺度地质体引起的绕射波,可提高小尺度地质体成像的分辨率。由于绕射波的能量一般比反射波低好几个数量级,绕射波成像需要把绕射波从数据中分离出来。笔者提出用SVD算法直接在炮集上分离绕射波,然后对绕射波进行成像。与其它分离法相比,该方法在原理和实现上都更为简单。数值计算表明,SVD方法能很好地从全波场数据中分离出绕射波。对合成的数据加上一定程度的噪声时,SVD方法仍然能很好地适用。基于SVD分离绕射波的关键是奇异值序列的截断,这需要对不同的数据进行试验,以致数据分离后,绕射波的能量占主要部分。绕射波成像结果有助于小尺度地质体的识别,而综合绕射波成像结果以及全波场成像结果能够更好地解释小尺度地质体。Diffraction originating from small- scale bodies is treated as noise in routine processing;however,it contains much information about the small-scale geological bodies,which may improve the resolution of the image.The first step of diffraction imaging is separating diffraction from the full record,since the energy of the diffraction is much weaker than the reflection.In this paper,the authors studied diffraction imaging which was separated directly on shot gather by using SVD algorithm.Compared with other separation methods,the theory and achievement of the separation directly on shot gather are easier.Numerical results show that SVD can separate diffraction from the full record well,even when noise is added to the data.The key of the method is to solve the problem as to which parts of the singular values should be intercepted while the remains could be used to reconstruct the wave-field,which requires testing various kinds of data.The results of the diffraction wave imaging are useful for the identification of small-scale geological bodies,and integrating diffraction wave imaging results with full wave imaging results can lead to a better interpretation.

关 键 词：小尺度地质体 绕射波成像 SVD 

分 类 号：P631.4[天文地球—地质矿产勘探]