Thomsen参数对VTI介质克希霍夫叠前深度偏移的影响  

The influence of Thomsen parameters on Kirchhoff prestack depth migration in VTI media

作　　者：周巍[1] 郭全仕[1] 刘旭跃[1] 宋林[1] 

机构地区：[1]中国石油化工股份有限公司石油物探技术研究院,南京211103

出　　处：《地球物理学进展》2014年第6期2866-2873,共8页Progress in Geophysics

摘　　要：为了适用高精度、微细构造勘探发展的需求,各向异性偏移正逐步在生产中得到应用,为了加深对各向异性介质的研究,更好地进行各向异性偏移,针对横向各向同性介质,从VTI介质克希霍夫叠前深度偏移生成的共成像点道集出发,根据偏移距深度比的大小,推导出了以Thomsen参数vp0、ε和δ(或vnmo和η)表征的VTI介质共成像点道集剩余深度差方程.通过单界面的VTI介质模型,对由Thomsen不准确引起的共成像点道集剩余深度差进行定量分析.利用各向异性Hess模型数据,通过改变各向异性参数的数值,考察对各向异性克希霍夫叠前深度偏移对参数变化的敏感性,分析了Thomsen参数对各向异性克希霍夫叠前深度偏移的影响.计算结果表明:垂向速度vp0只影响成像深度,对同相轴的横向连续性没有影响;正常时差速度vnmo影响整个偏移的效果,不仅影响成像深度,而且影响同相轴的横向连续性;η和ε类似,对偏移的影响远远小于速度的影响,速度是最敏感的参数.In order to meet the requirements of high precision,fine structure exploration demand,anisotropic migration is gradually applied in production,in order to deepen the study of anisotropic medium,better anisotropic migration For the transverse isotropic medium,basing on common imaging point gathers generated by Kirchhoff prestack depth migration in VTI media,and according to the size of the offset to depth ratio,deriving the residual depth difference equation using Thomsen parameters vp0,εandδ（or vnmoandη）of common imaging point gathers for VTI media.Through single interface model of VTI media,quantitativing about the residual depth difference of common imaging point gathers which is caused by the incorrect of Thomsen parameters.For data of anisotropic Hess model,do anisotropy Kirchhoff prestack depth migration by using the Thomsen with error parameters respectively,and then analyzes the sensitivity of anisotropic depth migration on Thomsen parameters and the effect of Thomsen parameters on the anisotropic Kirchhoff prestack depth migration. Results indicate that vertical velocity vp0 influence depth of migration only,and has no influence on the continuity of the event;normal move out velocity vnmoinfluence the whole result mostly not only on the depth of migration but also on the event continuity;the influence ofηandεis alike,and is far less than that of the velocity,the velocity is still the most sensitive parameter.

关 键 词：THOMSEN参数 叠前深度偏移 共成像点道集 VTI介质 

分 类 号：P631[天文地球—地质矿产勘探]