地球物理学进展 ›› 2020, Vol. 35 ›› Issue (6): 2203-2210.doi: 10.6038/pg2020EE0011

• 应用地球物理学Ⅰ(油气及金属矿产地球物理勘探) • 上一篇    下一篇

VTI介质速度与δ参数qP波全波形反演

孙史磊1,2(), 毛伟建1,*(), 任志明3, 李振春3   

  1. 1.中国科学院精密测量科学与技术创新研究院计算与勘探地球物理研究中心,大地测量与地球动力学国家重点实验室,武汉 430077
    2.中国科学院大学,北京 100049
    3.中国石油大学(华东)地球科学与技术学院,青岛 266580
  • 收稿日期:2020-01-13 修回日期:2020-08-06 出版日期:2020-12-20 发布日期:2020-12-26
  • 通讯作者: 毛伟建 E-mail:sunshilei@asch.whigg.ac.cn;wjmao@asch.whigg.ac.cn
  • 作者简介:孙史磊,男,博士研究生,主要从事各向异性地震成像和全波形反演研究. E-mail: sunshilei@asch.whigg.ac.cn
  • 基金资助:
    国家重点研发计划项目“超深层重磁电震勘探技术研究”(2016YFC0601101);中国石油天然气集团公司项目“深层与非常规物探新方法新技术”(2019A-33)

Velocity and δ parameter quasi-P waves full waveform inversion in VTI media

SUN Shi-lei1,2(), MAO Wei-jian1,*(), REN Zhi-ming3, LI Zhen-chun3   

  1. 1. Center for Computational and Exploration Geophysics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences;State Key Laboratory of Geodesy and Earth’s Dynamics,Wuhan 430077, China
    2. University of Chinese Academy of Sciences, Beijing 100049,China
    3. School of Geoscience, China University of Petroleum (East China), Qingdao 266580, China
  • Received:2020-01-13 Revised:2020-08-06 Online:2020-12-20 Published:2020-12-26
  • Contact: MAO Wei-jian E-mail:sunshilei@asch.whigg.ac.cn;wjmao@asch.whigg.ac.cn

摘要:

获取准确的速度与各向异性参数模型,是全波形反演的主要目标.由于各向异性参数的敏感性较差,常规全波形反演方法很难同时得到满意的速度和各向异性参数模型.本文提出一种新的VTI介质qP波全波形反演方法.采用动校正速度参数化方式得到新的VTI介质qP波方程,改善各向异性参数δ对近偏移距数据的敏感性.在新的方程中,推导了VTI介质全波形反演梯度公式.基于敏感核分析设计了合理的分步反演策略,来缓解不同参数之间的串扰,进而提高速度和各向异性参数的反演精度.模型算例表明,新的反演策略能够有效提高速度和δ参数的反演精度.分步反演方法在非线性更强的各向异性反演中,能够得到更接近真实值的反演结果.

关键词: 各向异性, 多参数反演, 全波形反演, 分步反演策略

Abstract:

Obtaining velocity and anisotropic parameter is considered as the main task of Full Waveform Inversion (FWI). Parameter estimation in an inhomogeneous anisotropic medium offers many challenges: Because of the poor sensitivity of anisotropic parameter, conventional anisotropic acoustic full waveform inversion methods fail to simultaneously invert for desirable velocity and anisotropic parameter; Trade-off between parameters impedes the resolvability. In multiparameter full waveform inversion, it’s essential that perturbation radiation pattern shows the parameter resolution possibilities and limits.

In this paper, we propose a new quasi-P waves FWI method in VTI (vertical transverse isotropy) media.We exploit the NMO (Normal Moveout) velocity parameterization to enhance the sensitivity of anisotropic parameter δ on the near-offset data. We derived the FWI gradient formula in new VTI equation. Based on the sensitivity analysis, we develop a hierarchical inversion workflow to relieve the crosstalk between different parameters and further improve the accuracy of velocity and anisotropic parameter models. The application on synthetic proves the effectiveness of our method on accuracy velocity and δ result. Considering anisotropy intensifies nonlinearity of inversion system, hierarchical inversion can contribute to obtaining more reliable inversion result.

Key words: Anisotropic, Multi-parameter, Full Waveform Inversion (FWI), Hierarchical inversion workflow

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