用户名: 密码: 验证码:
基于分频处理的叠前地震资料中面波压制
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
为了满足日益增长的能源需求,地震勘探已经从东部转移到西北部,从平原转移到沙漠,在这些地区采集到的地震资料中包含着很强的线性干扰和面波,其中面波的存在使得地震数据的信噪比急剧降低,有效性也遭到了极大的破坏。因此,必须对叠前资料中的面波干扰进行压制,而常用的面波处理方法如f-x滤波,f-k滤波,小波变换等,已不能满足这种需要。
     论文首先介绍了面波特点及多尺度分析的基本理论和性质,接着利用面波与有效波在频谱上的差异,分别采用多尺度变换中的二维小波变换和Curvelet变换,将地震记录分解到不同的频带内,只在面波的优势频段内进行压制处理,以保证其他频段的有效信号不会受到损伤。主要研究内容如下:
     首先,对地震记录做二维小波变换,在频率波数域中确定面波的优势频段;然后,对这些区域的小波系数进行阈值处理,本文将面波压制中的阈值选取与图像处理里的阂值构造方法联系起来,引入了均值及直方图两种图像阈值方法,并将其与常用的两种阈值函数分别应用到理论模型及实际地震数据的面波压制中,对比处理后的结果发现:地震记录经直方图阈值方法处理之后,其信噪比及分辨率都得到了明显提升。最后,将本文提出的基于小波变换及直方图阈值的面波压制算法与常用的面波处理方法分别应用到实际地震资料处理中,实验结果表明:本文提出的算法在压制面波的同时有效信号也得到了增强,处理效果要优于常用处理方法。
     接着,采用Curvelet变换对地震数据进行处理,它是在小波分析基础上发展起来的且能够最优表示具有曲线奇异的二维信号。算法具体思路为:首先对地震资料进行Curvelet变换,在Curvelet域中确定面波的优势频带;其次根据面波视速度低的特点,选择其在Curvelet域内对应的方向系数矩阵,利用本文建立的时域角度与Curvelet域方向的对应关系,只需根据面波在地震记录中的角度范围,就可确定其在Curvelet域的系数矩阵;接着,利用本文改进的加权均值阈值方法及其他三种阈值,对已确定存在面波的方向系数矩阵进行迭代阈值处理。理论模型及实际地震记录均证明了改进阈值的有效性。
     最后,将本文提出的两种分频算法分别对实际地震资料进行面波压制,通过对处理结果分析发现:两种算法都能很好的压制面波,且Curvelet变换分频算法在有效波的连续性保持上要强于小波分频方法。
To meet the increasing demand of energy, seismic exploration has been shifted from the east to the northwest and from plains to deserts, where the seismic data gathered are always contaminated by severe linear noise and surface wave. With the presence of surface wave, the signal-to-noise ratio of the seismic data decreases rapidly, and the validness of the seismic data has been gravely damaged. Therefore, the surface wave in the pre-stack must be suppressed, while the conventional denoising methods, such as f-x filtering, f-k filtering, wavelet transform and so on, perform ineffectively to suppress surface wave.
     In this paper, we first introduce the characteristics of the surface wave, and the basic theory and properties of multi-scale analysis. Then, based on the differences of spectrum between surface wave and the reflection signal, the seismic data has been sorted into different bands using the 2-D wavelet transform and Curvelet transform respectively, both of which are able to achieve multi-scale transform. With regard to the protection of signals in other bands, the processing has been applied to band dominated by surface wave. The main contents of the paper are as follows:
     First,2-D wavelet transform was exploited to treat seismic record. The dominant frequency band of the surface wave in the frequency-wave number domain was determined prior to other treatments. Meanwhile, a practical connection was established between the selection of thresholds and methods of constructing thresholds in image processing, which paved the way for the introduction of average threshold and histogram threshold. In the second place, wavelet coefficients of the determined band of surface wave were further segregated with the two proposed image thresholds. These two image thresholds and two other common threshold functions were applied to theoretical analysis and actual seismic data respectively and results showed that the signal-to-noise ratio and the resolution of the seismic data were improved remarkably through the processing of histogram threshold. In the last place, the algorithm posed in this paper based on the wavelet transform and histogram threshold, together with conventional methods, was utilized to suppress surface wave in actual seismic data, which demonstrated that the proposed algorithm effectively suppressed surface wave and enhanced the reflection signal.
     Then, Curvelet transform was implemented for the processing of seismic data, which has been proposed as an alternative to wavelet transform on the basis of wavelet analysis and is equipped with the ability to best represent two-dimensional signal with some plane curve singularities. The critical steps of Curvelet transform are specified as follows:Step 1. Seismic data was processed in the utilization of Curvelet transform to determine the leading band of surface wave in the Curvelet domain; Step 2. A corresponding relationship between the time domain and the direction of Curvelet domain was advanced for the purpose of defining Curvelet coefficient matrix in various orientations just according to the angle ranges of surface wave, which takes advantages of low apparent velocity of surface wave; Step 3. The Curvelet coefficient matrix was iterated through the proposed threshold derived from weighted average and other three thresholds. Compared with the other three thresholds, both theoretical model analysis and processing of actual seismic data demonstrated the effectiveness of the improved threshold.
     Finally, the two proposed algorithms are applied to actual suppression of surface wave in seismic data respectively, and comparative analysis of results proved that Curvelet transform performed more effectively to maintain the continuity of the reflection signal than wavelets.
引文
[1]刘天放,张爱敏等.地震勘探原理及方法[M].煤炭工业出版社,1996:17-61.
    [2]付燕.人工地震信号去噪方法研究[D].西北工业大学博士学位论文.2002:1-17.
    [3]熊章强,周竹生,张大洲.地震勘探[M].中南大学出版社,2010:10-85.
    [4]王有新.应用地震数据处理方法[M].石油工业出版社,2009:1:148.
    [5]姚姚.地震波场与地震勘探[M].地质出版社,2006年:75-142
    [6]Rayleigh L. On waves propagated along the plane surface of anelastic solid[J]. Proceedings of the London Mathematic Society,1887,17:4-11.
    [7]何樵登,韩立国,朱建伟等.地震波理论[M].吉林大学出版社,2005:70-77.
    [8]李媛媛.小波变换去除面波的方法研究[D].长安大学硕士学位论文.2004:4-9.
    [9]李卫忠,张明振,王成礼等.压制面波的波场分离方法[J].石油地球物理勘探,1998,33(5):679-690.
    [10]T. S. Durrani, D. Bisset. The Radon Transform and its Properties[J]. Geophysics.1984,49(8):1180-1187.
    [11]罗省贤,李录明.几种叠前去噪方法[J].石油地球物理勘探,1997,32(3):411-417.
    [12]胡天跃.地震资料叠前去噪技术的现状与未来[J].地球物理学进展,2002,17(2):218-223.
    [13]张军华,吕宁,田连玉等.地震资料去噪方法技术综合评述[J].地球物理学进展,2006,21(2):546-553.
    [14]刘洋,王典,刘财.数学变换方法在地震勘探中的应用[J].吉林大学学报.2005:1-8.
    [15]詹毅.地震资料叠前去噪方法研究[D].成都理工大学博士学位论文.2005:81-96.
    [16]张贤达.现代信号处理[M].第二版.清华大学出版社,2007:362-431.
    [17]D. Gabor. Theory of communication[J]. J.Inst.Electr.Eng.1946,93:429-457.
    [18]Jaideva C.Goswami,Andrew K.Chan小波分析理论、算法及其应用[M].许天周,黄春光译.国防工业出版社,2007:45-84.
    [19]J.Morlet. Sampling theory and wave propagation[C]. Proc.51st Annual International Meeting of the Society of Exploration Geophysicists, Los Angeles,1981.
    [20]J. Morlet, G. Arens, E. Fourgeau, D.Giard. Wave propagation and sampling theory-Part Ⅱ:Sampling theory and complex waves[J]. Geophysics.1982, 47(2):222-236.
    [21]E J. Candes, D L. Donoho. Curvelets-A Surprisingly Effective Nonadaptive Representation For Objects with Edges[M]. TN:Vanderbilt University Press, 1999.
    [22]E J. Candes, D L. Donoho. New Tight Frames of Curvelets and optimal Representations of Objects with C2 Singularities[J]. Commun. Pure Appl. Math.2002,57:219-266.
    [23]E J. Candes, L Demanet, D L.Donoho, Lexing Ying. Fast Discrete Curvelet Transforms[R]. Applied and computational mathematics, California Institute of Technology,2005:1-43.
    [24]Ingrid Daubechies小波十讲[M].李建平,杨万年译.国防工业出版社,2004:9-140.
    [25]葛哲学,沙威.小波分析理论与MATLAB R2007实现[M].电子工业出版社,2007:1-205.
    [26]孙延奎.小波分析及其应用[M].机械工业出版社,2005:35-58.
    [27]S G. Mallat. A Theory for Multiresolution Signal Decomposition:The Wavelet Representation[J]. IEEE Transactions on Pattern Analysis and Machine Intelligence.1989,11(7):674-692.
    [28]S G. Mallat. Multifrequency Channel Decompositions of Images and Wavelet Models[J]. IEEE Transactions on Acoustics Speech and Signal Processing. 1989,37(12):2091-2110.
    [29]周怀来.基于小波变换的地震信号去噪方法研究与应用[D].成都理工大学硕士学位论文.2006:7-24.
    [30]S G. Mallat信号处理的小波导引[M].杨力华,戴道清,黄文良,湛秋辉译.第二版,机械工业出版社,2002:230-238.
    [31]E J. Candes. Ridgelet:Theory and Application[D]. Ph. D. Thesis, Statistics, Stanford.1998.
    [32]焦李成,侯彪,王爽等.图像多尺度几何分析理论与应用—后小波分析理论与应用[M].西安电子科技大学出版社,2008:1-113.
    [33]闫敬文,屈小波.超小波分析及应用[M].国防工业出版社,2008:21-31.
    [34]E J. Candes, D L. Donoho. Continuous Curvelet Transform Ⅰ. Resolution of the Wavefront Set[J]. Applied and Computational Harmonic Analysis.2005, 19:162-197.
    [35]E J. Candes,D L. Donoho. Continuous Curvelet Transform Ⅱ. Discretization and frames[J]. Applied and Computational Harmonic Analysis.2005,19: 198-222.
    [36]J L. Starck, E J.Candes, D L.Donoho. The Curvelet Transform for Image Denoising[J]. IEEE Transactions on image processing,2002,11(6):670-684.
    [37]甘其刚,彭大钧.叠前时空域线性干扰的衰减及应用[J].石油物探.2004,43(2):123-125.
    [38]居兴华.地震资料分频处理的应用及效果[J].物探与化探.1994,18(5):331-338.
    [39]蔡希玲,吕英梅.地震数据时频分析与分频处理[J].勘探地球物理进展.2005,28(4):265-270.
    [40]Hakan Karsl, Yusuf Bayrak. Using the Wiener-Levinson algorithm to suppress ground-roll[J]. Journal of Applied Geophysics.2004,55:187-197.
    [41]J. K Welford, R Zhang. Ground-roll suppression from deep crustal seismic reflection data using a wavelet-based approach:A case study from western Canada[J]. Geophysics.2004,69(4):877-884.
    [42]A J. Deighan, D R. Watts. Ground-roll suppression using the wavelet transform[J]. Geophysics.1997,62(6):1898-1903.
    [43]G. Corso, P S. Kuhn, L S. Lucena, Z D. Thome. Seismic ground roll time-frequency filtering using the Gaussian wavelet transform[J]. Physica A. 2003,318:551-561.
    [44]Zhou Yu, John Ferguson, George McMechan,Phil Anno. Wavelet-Radon domain dealiasing and interpolation of seismic data[J]. Geophysics.2007, 72(2):41-49.
    [45]Xuewei Liu.Ground roll suppression using the Karhunen-Loeve transform[J]. Geophysics.1999,64(2):564-566.
    [46]吴招才,刘天佑.地震数据去噪中的小波方法[J].地球物理学进展.2008,23(2):493-499.
    [47]杨忠民,黄大云.小波变换在提高资料的信噪比和分辨率中的应用[J].石油地球物理勘探.1994,29(5):623-629.
    [48]覃天.基于小波分频叠前相干噪声压制方法[J].地球物理学进 展.2009,24(4):1426-1430.
    [49]张华,潘冬明,张兴岩.二维小波变换在去除面波干扰中的应用[J].石油物探.2007,46(2):147-150.
    [50]R Zhang, D Trad, T J Ulrych. Hybrid, wavelet transform based,noise attenuation[J]. Integrated Computer-Aided Engineering.2005,12:91-98.
    [51]D L. Donoho. De-Noising by Soft-Thresholding[J]. IEEE Transactions on Information Theory.1995,41(3):613-627.
    [52]付忠良.图像阈值选取方法的构造[J].中国图象图形学报.2000,5:466-469.
    [53]Rafael C. Gonzalez, Richard E. Woods数字图像处理[M].阮秋奇,阮宇智.第二版.电子工业出版社,2004:334-335.
    [54]Hao Shan, Jianwei Ma, Huizhu Yang. Comparisons of wavelets, contourlets and curvelets in seismic denoising[J]. Journal of Applied Geophysics.2009, 69:103-115.
    [55]E J. Candes. Monoscale Ridgelet for the Representation of Images with Edges[R]. Tech.Report, Department of Statistics, Stanford University,1999.
    [56]F J Herrmann, D Wang, G Hennenfent etc. Curvelet-based seismic data processing:a multiscale and nonlinear approach[J].Geophysic.2008,73(1) A1-A5.
    [57]Carson Yarham, Daniel Trad, Felix J.Herrmann. Curvelet processing and imaging:adaptive ground roll removal[C]. In Expanded Abstracts. CSEG, 2004.
    [58]J Ma, G. Plonka. A Review of Curvelets and Recent Applications[J]. IEEE Signal Process.2010,27:118-133.
    [59]刘冰.基于Curvelet变换的地震数据去噪方法研究[D].吉林大学硕士学位论文.2008:6-41.
    [60]Linfei Wang, Huaishan Liu, Siyou Tong, Jin Zhang, ZhiQiang Wu. Curvelet-based Noise Attenuation in Prestack Seismic Data[C]. Education Technology and Training & Geoscience and Remote Sensing,.2008:61-64.
    [61]Zhiyu Zhang,Xiaodan Zhang,Haiyan Yu,Xuehui Pan.Noise suppression based on a fast discrete curvelet transform[J].Journal of Geophysics and Engineering.2010,7:105-112.
    [62]Ramesh Neelamani,Anatoliy I.Baumstein,Dominique G.Gillard etc.Coherent and random noise attenuation using the curvelet transform.The Leading Edge.2008.240:248

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700