VTI介质SH-SH波地震反演方法研究  

Study on seismic inversion method of SH-SH wave in VTI media

作　　者：王波[1] 张峰[1] 代福材 李向阳[1] WANG Bo;ZHANG Feng;DAI FuCai;LI XiangYang(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《地球物理学报》2023年第5期2112-2122,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42122029);中国石油天然气集团有限公司“物探应用基础实验和前沿理论方法研究”(2022DQ0604-02)和“物探岩石物理与前沿储备技术研究”课题六“三维弹性波数据处理新方法探索研究”(2021DJ3506)共同资助

摘　　要：近年来,随着横波可控震源技术的发展,国内外已经实现了纯横波地震勘探.相较于地震纵波,地震横波对横波阻抗、横波速度尤其是各向异性参数变化更为敏感,因此地震横波能够用来更好地估算上述地层参数.VTI(具有垂直对称轴的横向各向同性)是地层介质中广泛存在的一种各向异性形式,对振幅随偏移距变化(AVO)影响显著.本文提出了一种改进的VTI介质SH-SH波反射系数近似公式,新公式具有较高的精度且仅包含两项待求参数:横波阻抗和水平横波(SH波)速度.基于新方程建立了VTI介质SH-SH波反演方法,该方法相比VTI介质的PP波反演不确定性明显下降,同时降低了常规PP波各向异性反演对大角度数据的要求.为了获得独立的横波各向异性参数,进一步地提出了一种基于岩石物理关系的横波各向异性参数估算方法.合成地震数据测试和柴达木盆地九分量地震勘探实际地震数据应用结果表明,新方法能够准确地预测地层的横波阻抗、水平横波(SH波)速度、各向异性参数,为各向异性地层的岩性解释和油气储层预测提供了可靠的解决方案,从而深化了横波地震勘探的应用潜力.Recently,shear-wave exploration has been achieved worldwide with the development of shear-wave vibrator.Compared with seismic P-wave,seismic shear waves are more sensitive to shear-wave impedance,shear-wave velocity,and anisotropy parameters.Therefore,seismic shear wave can be used to better estimate the above parameters.VTI(transversely isotropic media with a vertical axis of symmetry)is a common anisotropy form of subsurface media,and it has significant influence on the seismic Amplitude Variation with Offset(AVO).This paper proposes a modified SH-SH wave reflection coefficient approximation equation for VTI media.The new formula has high accuracy and contains only two model parameters to be inverted:the shear wave impedance and the shear wave(SH-wave)horizontal velocity.Based on the new formula,we develop a SH-SH wave inversion method.Compared with PP wave inversion for VTI media,the uncertainty of this new inversion method is largely reduced,and the requirement of large-angle data of the conventional PP wave anisotropic inversion is also reduced.In order to obtain the independent S-wave anisotropy parameters,a rock physics-based anisotropy parameter inversion method is further developed.The synthetic data experiment and the practical seismic data application in the nine-component seismic exploration area of Qaidam Basin show that the proposed method can obtain accurate and high-resolution shear wave anisotropy parameters.The research provides a reliable solution for lithology interpretation and oil and gas reservoir prediction of anisotropic formations,thus deepening the application potential of shear wave seismic exploration.

关 键 词：横波(SH-SH波) VTI介质 横波阻抗 横波速度 横波各向异性参数 

分 类 号：P631[天文地球—地质矿产勘探]