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在许多地质条件下,气-水界面处的强反射为地震记录中的多次波提供了大部分的能量。在此,我们阐述一种运用众所周知的恒定嵌入技术推导出一个地震记录的反射算子模型来进行自由界面的多次波衰减的方法。我们是在二维平面波域中应用该方法的,用不同的射线参数进行耦合,并考虑地下地质构造的横向变化。当这种横向变化较平缓时,地震数据在二维平面波域中压缩得很好,得到的最终有限带宽矩阵也大大减少了计算费用。这种处理方法的一个重要特点就是它的灵活性,也就是允许从任意选定的反射中剔除多次波。为了得到不含多次波的资料,基于波动理论的多次波衰减方法或是试图估算出源函数或是推算地下界面反射系数。而我们的方法却是综合利用了上述两种方法,即首先利用反射系数预测多次波旅行时间,然后寻求一个源函数预测振幅。模拟和实测数据的例子都表明,这种方法用来衰减地面多次波是稳定而成功的。
Under many geological conditions, strong reflections at the gas-water interface provide most of the energy for multiple waves in seismic records. Here, we describe a method of deriving a reflection operator model of seismic records to perform multiple attenuation of free interfaces using the well-known constant embedding technique. We apply this method in a two-dimensional plane wave domain, couple it with different ray parameters, and consider lateral changes in the subsurface geological structure. When this lateral variation is gentle, the seismic data is compressed well in the two-dimensional plane wavefield and the resultant finite bandwidth matrix is greatly reduced. An important feature of this approach is its flexibility, which allows the elimination of multiples from any chosen reflection. In order to get the data without multiples, the multiple attenuation method based on wave theory is trying to estimate the source function or calculate the reflection coefficient of the subsurface interface. However, our method is to comprehensively utilize the above two methods, that is, the reflection coefficient is used to predict the traveling time of multiple waves first, and then a source function is used to predict the amplitude. Examples of both simulated and measured data indicate that this method is stable and successful in attenuating ground multiples.