| 沙漠地区地震勘探随机噪声建模及其在噪声压制中的应用 |
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| 引用本文： | 李光辉,李月.沙漠地区地震勘探随机噪声建模及其在噪声压制中的应用[J].地球物理学报,2016,59(2):682-692. |
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| 作者姓名： | 李光辉 李月 |
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| 作者单位： | 吉林大学信息工程系, 长春 130012 |
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| 基金项目： | 深部矿产资源立体探测技术及实验研究(SinoProbe-03)和国家自然科学基金重点项目(41130421)共同资助. |
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| 摘 要： | 随机噪声是影响地震勘探有效信号的主要因素,其存在大大降低了地震记录的信噪比.在噪声压制方法不断被改进的同时,对随机噪声特性进行研究,了解噪声的产生机制是对其进行压制的先决条件,目前对噪声的研究主要是特性研究以寻找规律性,对其进行定性定量的分析还比较少.本文根据塔里木沙漠地区实际采集环境,考虑到噪声的连续性给计算带来的不便,假设各类噪声源以点源的形式分布在检波器周围,依据相应理论确定各类噪声源的源函数,其激发的噪声经由波动方程传播,将随机噪声作为各类噪声源共同作用的综合波场,建立随机噪声的理论模型.通过分析不同种噪声对地震记录的影响,选取合适的滤波方法对其进行压制,实验结果表明,通过建立沙漠地区随机噪声的理论模型,为选择有效的滤波方法,提高地震记录信噪比起到理论指导作用.
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| 关 键 词： | 地震勘探随机噪声 波动方程 噪声建模 噪声压制 |
| 收稿时间： | 2015-07-17 |
Random noise of seismic exploration in desert modeling and its applying in noise attenuation |
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| LI Guang-Hui,LI Yue.Random noise of seismic exploration in desert modeling and its applying in noise attenuation[J].Chinese Journal of Geophysics,2016,59(2):682-692. |
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| Authors: | LI Guang-Hui LI Yue |
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| Institution: | Department of Information and Engineering, Jilin University, Changchun 130012, China |
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| Abstract: | Random noise is one of key factors which influence valid signals of seismic exploration, and it weakens the signal to noise ratio (SNR) of seismic records seriously. It is the first request to study noise characteristics and generation while filtering methods are improved continuously. At this stage noise characteristics research emphasizes searching its regularity, but much less qualitative and quantitative analysis. In this paper, seismic random noise is classified into natural noise and cultural noise according to the reason that noise is generated. Considering convenience to the calculation, it is assumed that different kinds of noise sources are distributed around the geophones as point sources in their areas appointed. The noise source functions are decided according to the corresponding theories, experience and references. It is assumed that their excitation waves propagate by wave equation and seismic random noise is considered as a superposed wave-field excited by all of the source. The theoretical model of random noise is obtained by solving the non-homogeneous wave equations with different source functions and superposing all of the solutions. #br#The characteristics of different kinds of noise in the seismic records can be shown through modeling random noise. A simulated noise record is compared with a section of field seismic data in the desert in Tarim, including spectral feature, kurtosis, skewness, root-mean-square, etc. From the comparative results, it can be seen the simulated noise is similar with the real noise, which shows the feasibility of the modeling method.#br#The appropriate filtering method is chosen for noise attenuation according to analyzing all kinds of noise characteristics in seismic records. In the desert, near-field cultural noise is the key component of random noise, based on which, complex diffusion filtering is selected, and the filtered results including the artificial synthetic and actual seismic records are compared with the results of time frequency peak filtering which is a popular method in seismic random noise attenuation in recent years. The comparative results show that complex diffusion filtering is more suitable for the random noise in Tarim, which demonstrates that seismic random noise modeling can provide theoretical guidance to choosing appropriate filtering method. |
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| Keywords: | Seismic exploration random noise Wave equation Noise modeling Noise attenuation |
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