北京大学学报自然科学版 ›› 2020, Vol. 56 ›› Issue (3): 427-435.DOI: 10.13209/j.0479-8023.2020.021

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基于矢量波数变换法的主动源瑞雷波多模式提取方法在近地表地层结构探测中的应用研究

苏悦1, 杨振涛2,†, 杨博3, 赵亮4   

  1. 1. 北京大学地球与空间科学学院, 北京 100871 2. 南方科技大学地球与空间科学系, 深圳 518055 3. 中南大学地球科学与信息物理学院, 长沙 410083 4. 东方地球物理公司物探技术研究中心, 涿州 072751
  • 收稿日期:2019-05-12 修回日期:2019-06-29 出版日期:2020-05-20 发布日期:2020-05-20
  • 通讯作者: 杨振涛, E-mail: yangzt(at)sustech.edu.cn
  • 基金资助:
    国家重点研发计划(2018YFC0603600)和国家自然科学基金(41974047)资助

Application Research of Active Source Rayleigh Wave Multi-Mode Extraction Method Based on Vector Wavenumber Transformation Method in Near Surface Stratigraphic Structure Detection

SU Yue1, YANG Zhentao2,†, YANG Bo3, ZHAO Liang4   

  1. 1. School of Earth and Space Sciences, Peking University, Beijing 100871 2. Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen 518055 3. School of Geosciences and Info-physics, Central South University, Changsha 410083 4. Bureau of Geophysical Prospecting Inc., China National Petroleum Corporation, Zhuozhou 072751
  • Received:2019-05-12 Revised:2019-06-29 Online:2020-05-20 Published:2020-05-20
  • Contact: YANG Zhentao, E-mail: yangzt(at)sustech.edu.cn

摘要:

基于瞬态多道面波分析法(MASW)的数据采集方式, 对矢量波数变换法(VWTM)、相移法和高分辨率拉东变换法3种瑞雷波频散成像方法进行对比分析。首先, 采用合成地震数据对比3种方法的成像效果, 发现VWTM在成像精度和成像质量方面都有很大的优势, 成像分辨率高, 与理论频散曲线拟合准确, 高阶模式成像效果突出, 且抗噪能力也优于另两种方法。然后, 采用实际多道瞬态面波数据进行对比分析, 发现与相移法和拉东变换法相比, VWTM在瑞雷波基阶模式成像精度和高阶模式成像质量方面仍具有优势。采用遗传算法对比基阶与高阶频散曲线反演结果, 发现含有高阶模式的多模式频散曲线联合反演的多解性明显降低, 反演结果精度更高, 也更稳定。在实际瞬态瑞雷波勘探实践中, VWTM能够高质量地提取多模式瑞雷波频散特征, 可为多模式面波频散联合反演提供可靠的基础数据。研究结果表明, 将VWTM法与有效的反演方法相结合, 可以极大地提高瑞雷波浅地层探测能力和探测精度。

关键词: 瑞雷波, 矢量波数变换法(VWTM), 多道面波分析法(MASW), 高阶频散曲线, 遗传算法

Abstract:

Based on the array of the transient multi-channel analysis of surface waves (MASW), Rayleigh wave dispersion imaging methods including vector wavenumber transformation method (VWTM), phase shift, and highresolution linear Radon transform are used to carry out comparative analysis. First, the dispersion imaging results of synthetic data are compared to analyze the quality of the three methods. The VWTM is found superior to the other two in terms of resolution, accuracy of higher modes, fitting degree with theoretical dispersion curves and anti-noise property. In the actual Rayleigh wave detection, the VWTM can still has advantages in foundamental mode imaging accuracy and higher order modes imaging quality. Then the genetic algorithm is employed to invert the dispersion curves of fundamental mode and higher modes. The result is more accurate and stable when higher modes are combined in the inversion, it also performs much better in reducing non-uniqueness of inversion. The research shows that the VWTM can extract multi-mode characteristics of Rayleigh wave dispersion effectively and with high quality in field prospecting, which provides a reliable data foundation for joint inversion of multi-mode of Rayleigh wave dispersion curves. In conclusion, the VWTM combined with effective inversion method can remarkably improve the accuracy of near surface stratigraphic structure detection and has great potential in enhancing Rayleigh wave exploration capability.

Key words: Rayleigh wave, vector wavenumber transformation method (VWTM), multi-channel analysis of surface waves (MASW), higher-mode dispersion curves, genetic algorithm