提高反射地震成像分辨率的方法及应用
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摘要
地震分辨率是地震数据处理和偏移成像中的重要问题,特别是在油气田开发中具有实际意义。文章在地震偏移成像广义空间分辨率理论研究基础上,提出了基于空间分辨力理论实现反动校正拉伸方法来实现高分辨率水平叠加和实现最佳分辨率地震成像。文章以共中心点道集中各地震道分辨率随炮检距增大而降低为理论依据,说明动校正拉伸的形成原因,并且根据广义分辨率公式导出了非零炮检距各地震道相对于零炮检距地震道的拉伸因子。利用这个拉伸因子可将动校正后的拉伸波形校正为等价的零炮检距地震道的子波,与常规的水平叠加相比,拉伸校正后CMP道集的叠加剖面分辨率明显提高。文章从偏移成像分辨率理论出发提出了根据反射波的地质参数选取偏移孔径的条件,并通过数值试算证明了实现高分辨率最佳成像方法的可行性。
On the basis of the theory of generalized space resolution of seismic migration imaging, the high resolution horizontal stacking and optimal resolution seismic imaging may be realized by applying the inverse dynamic correction stretching method based on the theory. In the paper, according to the theory that the resolution of each seismic trace in common midpoint (CMP) gather can be reduced along with the increase in offset, the cause of forming dynamic correction stretching is explained and the stretching factor of the non-zero offset trace relative to the zero offset trace is derived in light of the generalized resolution formula. The stretch wave shape after dynamic correction can be corrected as the equivalent wavelet of the zero offset trace by use of the stretching factor, and, as compared with the conventional horizontal stocking, the resolution of the stacked section of CMP gather corrected by the stretching factor is greatly enhanced. In consideration of the theory of migration imaging resolution, the condition of selecting migration aperture in terms of the geological parameters of reflected waves is put forward in the paper. Through numerical calculation, it was proved that such an optimal imaging method with high resolution is feasible.
On the basis of the theory of generalized space resolution of seismic migration imaging, the high resolution horizontal stacking and optimal resolution seismic imaging may be realized by applying the inverse dynamic correction stretching method based on the theory. In the paper, according to the theory that the resolution of each seismic trace in common midpoint (CMP) gather can be reduced along with the increase in offset, the cause of forming dynamic correction stretching is explained and the stretching factor of the non-zero offset trace relative to the zero offset trace is derived in light of the generalized resolution formula. The stretch wave shape after dynamic correction can be corrected as the equivalent wavelet of the zero offset trace by use of the stretching factor, and, as compared with the conventional horizontal stocking, the resolution of the stacked section of CMP gather corrected by the stretching factor is greatly enhanced. In consideration of the theory of migration imaging resolution, the condition of selecting migration aperture in terms of the geological parameters of reflected waves is put forward in the paper. Through numerical calculation, it was proved that such an optimal imaging method with high resolution is feasible.
引文
1 MaZTetal.Quantitativeestimationofimagingresolu tion.72ndAnnInternatMtg,SocofExplGecphys,2002:2281-2284
2 马在田.反射地震成像分辨率的理论分析.同济大学学报(自然科学版),2005;(待刊)
3 RupertGB,ChunJH.Theblockmovesumnormal moveoutcorrection.Geophysics,1975;40:17-24
4 DunkinJW,LevinFK.Effectofnormalmoveoutona seismicpulse.Geophysics,1973;38:635-642
5 BrouwerJH.ImprovedNMOcorrectionwithaspecific applicationtoshallowseismicdata.Geophysicalprospec ting,2002;50:225-257
2 马在田.反射地震成像分辨率的理论分析.同济大学学报(自然科学版),2005;(待刊)
3 RupertGB,ChunJH.Theblockmovesumnormal moveoutcorrection.Geophysics,1975;40:17-24
4 DunkinJW,LevinFK.Effectofnormalmoveoutona seismicpulse.Geophysics,1973;38:635-642
5 BrouwerJH.ImprovedNMOcorrectionwithaspecific applicationtoshallowseismicdata.Geophysicalprospec ting,2002;50:225-257
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