基于正交多项式的高精度零炮检距地震道拟合
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摘要
提高零炮检距地震道的拟合精度是保幅地震资料处理的关键环节之一。相对于常规地震叠加技术,二阶多项式拟合技术能够提高零炮检距地震道的拟合精度。但是不同时刻地层反射信号的AVO特性是变化的,仅仅利用二阶多项式来实现零炮检距地震道拟合是达不到精度要求的。本文采用正交多项式描述CMP道集上不同时刻地层反射信号的AVO特性,建立正交多项式系数谱;并根据SVD估计有效波的能量,自适应地确定不同时刻拟合零炮检距地震道信号所需的阶次,实现高精度的零炮检距地震道拟合。合成记录和实际数据的处理表明该方法能够有效地减小零炮检距地震道拟合误差,提高拟合精度。
Improving the fitting precision of zero-offset seismic trace is one of key links of amplitude-preserved seismic data processing.In comparison with conventional seismic stack technique,the second-order polynomial fitting technique can improve the fitting precision of zero-offset seismic trace,but the AVO character of reflected signal is variation for the strata in different times,which means that only using second-order polynomial to implement the zero-offset seismic trace fitting is not enough.Using orthogonal polynomial to describe the AVO character of reflected signal for the strata in different times on CMP gathers and self-adaptive determining the orders needed for fitting the signals of zero-offset traces in different times based on the energy of useful waves evaluated by SVD,the paper realized high-precision zero-offset seismic trace fitting.The synthetic records and practical data processing showed that the method is able to effectively reduce the fitting errors of zero-offset seismic trace and improve the fitting precision.
Improving the fitting precision of zero-offset seismic trace is one of key links of amplitude-preserved seismic data processing.In comparison with conventional seismic stack technique,the second-order polynomial fitting technique can improve the fitting precision of zero-offset seismic trace,but the AVO character of reflected signal is variation for the strata in different times,which means that only using second-order polynomial to implement the zero-offset seismic trace fitting is not enough.Using orthogonal polynomial to describe the AVO character of reflected signal for the strata in different times on CMP gathers and self-adaptive determining the orders needed for fitting the signals of zero-offset traces in different times based on the energy of useful waves evaluated by SVD,the paper realized high-precision zero-offset seismic trace fitting.The synthetic records and practical data processing showed that the method is able to effectively reduce the fitting errors of zero-offset seismic trace and improve the fitting precision.
引文
[1]俞寿朋.高分辨率地震勘探.北京:石油工业出版社,1993
[2]文世鹏.数值分析.北京:石油工业出版社,1999
[3]Johansen T A,Brulan L,Lutro J.Tracking the AVO by using orthogonal polynomials.Geophysical pros-pecting,1995,43:245～261
[4]郑君里.信号与系统.北京:高等教育出版社,2000
[5]刘洋,李承楚.地震资料信噪比估计的几种方法.石油地球物理勘探,1997,32(2):257～262
[2]文世鹏.数值分析.北京:石油工业出版社,1999
[3]Johansen T A,Brulan L,Lutro J.Tracking the AVO by using orthogonal polynomials.Geophysical pros-pecting,1995,43:245～261
[4]郑君里.信号与系统.北京:高等教育出版社,2000
[5]刘洋,李承楚.地震资料信噪比估计的几种方法.石油地球物理勘探,1997,32(2):257～262
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