【作者】 桂丽华；

【导师】 尹忠科；

【作者基本信息】 西南交通大学 ， 信号与信息处理， 2010， 硕士

【摘要】 随着地震勘探技术的深入和发展,要求勘探目标越来越精细,面波是一种对地震记录信噪比影响较大的相干干扰,如果不很好地压制,会严重影响地震资料的后续处理及解释工作,传统的压制面波的方法都只是侧重考虑某一方面的单一特性或者仅依据某种条件假设等,尽管能有效地压制面波,但是在压制面波的同时有效波也会受到不同程度的损失。近几年来发展起来的基追踪(Basis Pursuit, BP)算法是信号稀疏。表示领域的一种新方法。它寻求从完备的(过完备)函数(基)集合中得到信号最稀疏的表示,即用尽可能少的基精确地表示原信号,从而获得信号的内在本质特性。根据地震信号的特性将此方法应用到地震资料处理中,为获得高分辨率的地震资料提供了新的研究方向。本文首先对面波分离与压制的发展及研究现状做了分析,然后介绍了目前常用去除面波的方法及信号稀疏分解基础知识,实现了基于BP的频率估计方法,实验结果证明了利用BP分解信号能够准确地估计出信号的频率,为BP分离地震信号提供了一定的方法基础。在第三章中,实现了基于BP的合成一维地震信号的时频分离,实验证明BP能够有效地分离出组成地震信号的各个子波,在BP分离地震信号的基础上提出了一种基于BP的面波分离与压制方法,该方法是基于稀疏分解的原理,以面波的频率特性和能量特性为依据,根据二维地震信号的实际频率范围及地震信号的结构特征建立白适应原子库,并从中筛选出能近似重建地震信号的重要原子,然后根据筛选出的重要原子分解系数以及参数来设置能量阈值和主频阈值范围,从每道地震信号分解结果中找出组成面波的原子重建该道的面波成分,用该道地震信号减去面波成分并得到该道压制面波后的地震信号,以达到分离与压制面波的效果。在第四章中,利用提出的BP分离与压制面波的方法对合成的二维地震记录进行了面波的分离与压制,与传统的一维傅里叶滤波方法和一维小波处理方法做对比,分别从主观和客观评价该方法的处理效果,证明了该方法在处理效果上的优越性。在第五章中,利用提出的BP分离与压制面波的方法对实际的地震剖面进行了面波的分离与压制,与传统的一维傅里叶滤波和一维小波处理方法对比,通过实验证明该方法对实际地震剖面处理效果较传统的方法仍然具有优势。更多还原

【Abstract】 With the development of seismic exploration technology, exploration targets required more and more sophisticated,surface wave is a coherent interference, which is a signal to noise ratio greater impact on the seismic records.The traditional method of surface wave suppression only focus on one aspect to consider a single feature, or assumptions based only on certain conditions, despite the effective suppression of surface wave, however, while the effective suppression of surface wave, effective wave will also be different degrees of loss. Developed in recent years, the Basis Pursuit algorithm is that the area of sparse signal a new approach,which sought the most sparse representation of signal from the complete (overcomplete) function (base) set, that is expressing the original signal exactly with base as little as possible, thereby obtain the intrinsic nature of the signal characteristics. According to the characteristics of seismic signals,this paper applied this method to the seismic data processing, which provides a new research direction in order to btain high-resolution seismic data.This paper first analyzes the development and current research situation of separation and suppression method of surface wave, then introduced the normal method of removal of surface wave and the basis knowledge of signal sparse decomposition, analysis of the frequency estimation method which is based on BP, experimental results show the using of BP decomposition the signal can accurately estimate the frequency of the signal,which provides the basis of a certain method for BP separating seismic signals. In the third chapter, the separation of time-frequency of the synthesized one-dimensional seismic signals based on BP was achieved, experimental proved BP can effectively isolate the various sub-wave which composed seismic signal, separation in BP based on the seismic signal, a separation and suppression method of surface wave based on BP is bring forward on the basis of BP separating seismic signals, this method is based on the sparse decomposition principle, according as the frequency characteristics and energy characteristics of surface wave, according to the actual frequency range of two-dimensional seismic signals and structural characteristics of the seismic signal establishes adaptive atom dictionary, and selected the importance atoms which can approximate reconstruct the seismic signal form the atom dictionary, then according to decomposition coefficients and parameters of the selected importance atoms set the energy threshold and the range of main_frequency threshold adaptively, identify the atoms which compose surface wave form the decomposition results of every seismic signal and reconstruct the surface wave component of this seismic signal, using of this seismic signal subtract the surface wave component and get the seismic signal which its surface wave component is suppressed, to achieve and the effect of separating and suppressing surface wave. In the fourth chapter, using of the proposed method of BP to separation and suppression of surface wave separate and suppress the surface wave of synthetic two-dimensional seismic record, comparing with the traditional one-dimensional Fourier filtering and one-dimensional wavelet processing method, respectively subjective and objective evaluate the treatment effect of the method, results show that the method’s superiority in the treatment effect. In the fifth chapter, using of the proposed method of BP to separation and suppression of surface wave separate and suppress the surface wave of the actual seismic profile, comparing with the traditional one-dimensional Fourier filtering and one-dimensional wavelet processing method, experimental results show this method still reflects its advantages in actual seismic data processing than the traditional methods.更多还原