基于S变换的初至拾取方法及应用
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摘要
初至的拾取是折射波资料分析、VSP处理和井间地震资料处理的基础工作。常规的初至拾取方法存在着较大的误差。Stockwell提出的S变换,可有效解决低信噪比地震记录初至拾取困难的问题。S变换后的单道地震记录,因其地震信号在初至起跳前后存在明显的频率差异,致使时频图上有明显的能量聚集。为检测该方法识别初至的容噪能力,设计了三种信噪比的理论记录,检测结果显示,不论地震信号波形的信噪比有多低,地震信号的时频谱都有明显的能量聚集存在,都可有效拾取地震信号的初至。实例表明,基于S变换的地震信号初至识别方法能够比较准确地拾取地震信号的初至。
The picking of first break is an essential work for refraction data analysis,VSP processing and cross-borehole seismic data processing.Rather large errors will be happened usually in conventional method of first break picking.Thus the S-transform was introduced by Stockwell,it can settle issues of difficult in low S/N ratio seismic recording first break picking.The one channel seismic recording after S-transforming,since the frequency differences existed between the seismic signals before and after first break onset have caused obvious energy accumulation on time-frequency graph.To check out the method's first break noise margin recognition capability,three S/N ratio theoretical records were designed,the checked results demonstrated that,no matter how low is the seismic signal waveform S/N ratio,obvious energy accumulation is existed in seismic signal time-frequency spectrum,and can pick up first breaks of seismic signal effectively.Examples demonstrated that,the first break picking based on S-transform can check out first break rather correctly.
The picking of first break is an essential work for refraction data analysis,VSP processing and cross-borehole seismic data processing.Rather large errors will be happened usually in conventional method of first break picking.Thus the S-transform was introduced by Stockwell,it can settle issues of difficult in low S/N ratio seismic recording first break picking.The one channel seismic recording after S-transforming,since the frequency differences existed between the seismic signals before and after first break onset have caused obvious energy accumulation on time-frequency graph.To check out the method's first break noise margin recognition capability,three S/N ratio theoretical records were designed,the checked results demonstrated that,no matter how low is the seismic signal waveform S/N ratio,obvious energy accumulation is existed in seismic signal time-frequency spectrum,and can pick up first breaks of seismic signal effectively.Examples demonstrated that,the first break picking based on S-transform can check out first break rather correctly.
引文
[1]李扬.时频分析技术在地震数据处理中的应用[D].江苏徐州:中国矿业大学,2009.
[2]左国平.地震记录初至拾取方法对比和研究[D],北京:中国地质大学,2006.
[3]Hiorkazu Moriya,Hiroaki Niitsuma.Precise detection of a P-wave in low S/N signal by using time-frequency representations of a trivial hologram[J].Geophysics,1996,61(5):l453-1466.
[4]Stockwell R G.A basis for efficient representation of the S-transform[J].Digital Signal Processing,2007,17:371-393.
[5]蔡希玲.地震数据时频分析方法研究及应用[D].成都:成都理工学院,2000.
[6]杨砚琪.分形在检测地震波初至方面的应用[J].中国煤田地质,1997,10(04).
[7]邹文,陈爱萍,顾汉明,等.S-变换初至拾取技术及其在复杂山区中的应用[J].石油天然气学报,2006,28(02).
[8]李宇,杨德义,邓辉,等.旅行时差值曲线方法在时间项反演中的应用[J].中国煤炭地质,2009,21(02).
[2]左国平.地震记录初至拾取方法对比和研究[D],北京:中国地质大学,2006.
[3]Hiorkazu Moriya,Hiroaki Niitsuma.Precise detection of a P-wave in low S/N signal by using time-frequency representations of a trivial hologram[J].Geophysics,1996,61(5):l453-1466.
[4]Stockwell R G.A basis for efficient representation of the S-transform[J].Digital Signal Processing,2007,17:371-393.
[5]蔡希玲.地震数据时频分析方法研究及应用[D].成都:成都理工学院,2000.
[6]杨砚琪.分形在检测地震波初至方面的应用[J].中国煤田地质,1997,10(04).
[7]邹文,陈爱萍,顾汉明,等.S-变换初至拾取技术及其在复杂山区中的应用[J].石油天然气学报,2006,28(02).
[8]李宇,杨德义,邓辉,等.旅行时差值曲线方法在时间项反演中的应用[J].中国煤炭地质,2009,21(02).
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