地球物理学进展 ›› 2018, Vol. 33 ›› Issue (4): 1358-1365.doi: 10.6038/pg2018BB0321

• 固体地球物理及空间物理学(大气、行星、地球动力学、重磁电及地震学、地热学) • 上一篇    下一篇

谱白化叠加方法在气枪信号检测中的应用

金震1,2,李山有1,蔡辉腾2,李培2,李海艳2,徐嘉隽2   

  1. 1. 中国地震局工程力学研究所和中国地震局地震工程与工程振动重点实验室,哈尔滨 150000
    2. 福建省地震局,福州 350000
  • 收稿日期:2017-10-18 修回日期:2018-07-22 出版日期:2018-08-20 发布日期:2018-09-13
  • 作者简介:金震,男,1985年生,云南大理人,工程力学研究所在读博士,现为厦门地震勘测研究中心工程师,主要从事地球深部构造方面的研究. (E-mail: 358450071@qq.com)
  • 基金资助:
    国家自然科学基金项目(41474071);地震行业科研专项项目(2015419015);中国地震局工程力学研究所基本科研业务费专项资助项目(2016A03)

Application of whitening stack method in picking up the air gun signal

JIN Zhen1,2,LI Shan-you1,CAI Hui-teng2,LI Pei2,LI Hai-yan2,XU Jia-jun2   

  1. 1. Institute of Engineering Mechanics, China Earthquake Administration, Key Laboratory of Earthquake Engineering and Engineering Vibration, China Earthquake Administration, Harbin 150000, China
    2. Earthquake Administration of Fujian Province, Fuzhou 350000, China
  • Received:2017-10-18 Revised:2018-07-22 Online:2018-08-20 Published:2018-09-13

摘要:

主动源气枪信号具有绿色环保,低频信号丰富,传播距离远,高重复性的特点,广泛运用于区域尺度深部探测和介质变化监测中.如何准确和高效的识别信号是气枪信号处理的难点也是重点.检测信号的能力取决于观测记录的信噪比,通常为了提高地震记录的信噪比,常用的方法有滤波,去噪和叠加.针对具有高重复性的气枪信号,通过叠加的手段提高信号信噪比.文中基于气枪信号的特征,推导了谱白化叠加与窄带线性叠加的等价关系,从数值模拟和实际气枪记录的角度,对线性叠加、谱白化叠加和加权叠加在信号捡拾能力方面进行了分析和研究.结果表明:相比于线性叠加和加权叠加,谱白化叠加具有与模版信号相似程度高,对弱信号捡拾能力强的特点,但是对于高信噪比信号,线性叠加的效果更好.另一方面,对实际记录分析验证了数值模拟分析的正确性、合理性.因此针对气枪信号近场应采用线性叠加,远场应采用白躁化叠加.而针对地震剖面中信号连续追踪可采用加权叠加结果,这是因为加权叠加提高信噪比最为明显;震相拾取建议采用线性叠加或谱白化叠加结果,这是因为以上两种方法不会产生相位偏移和相位畸变.

关键词: 气枪信号, 数值模拟, 信噪比, 线性叠加, 谱白化叠加

Abstract:

The active source gun signal has many advantages, such as environmental protection, low frequency signal, high propagation distance and high repeatability. It is widely used in deep detection and monitoring media changes of regional scale. How to identify signals accurately and efficiently is the key point of air gun signal processing. The ability to detect signals depends on the signal to noise ratio of observed records. In order to improve the signal-to-noise ratio of seismic records, filtering, denoising and superposition are often used. In order to improve the Signal to Noise Ratio (SNR) of gun signals with high repetition, the method of superposition is adopted to improve the signal to noise ratio. Here, we based on the characteristics of air gun signal, derived equivalence relation between linear superposition and spectrum whitening. From the point of view of numerical simulation and actual air gun recording, we analyze and study the signal pickup ability of linear superposition, spectral whitening superposition and weighted superposition. The result shows that:compared to the linear superposition and weighted superposition, spectrum whitening and template signal superimposed with high degree of similarity, the weak signal pickup ability. However, these capabilities have certain scope of application. On the other hand, the correctness and rationality of the numerical simulation analysis are verified by the analysis of the actual record. Therefore, the linear superposition of the near field of gun signal should be adopted, and the far field should be spectrum whitening. The signal in seismic section continuous tracking can be used weighted superposition of results, this is because the weighted sum of SNR is most obvious; seismic phase suggested by linear superposition or spectral whitening results, this is because of the above two methods will not produce phase shift and phase distortion.

Key words: air gun signal, numerical simulation, SNR, linear superposition, spectrum whitening

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