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所有已知的倾角时差(DMO)不是积分法算法需要在规则取样的固定偏移距剖面中选出地震资料。但是,文中介绍的倾角时差法能直接应用于炮点剖面记录,因此能处理那些在规则固定偏移距剖面中不能进行选择的资料。炮点倾角时差算子的定义与固定偏移距剖面的倾角时差算子是很相似。这两种算子在零偏移距面(即叠加面)上有相同投影的脉冲响应。因此,应用固定偏移距剖面中或炮点剖面中的倾角时差,都能提供同样的叠加剖面。倾角时差法可将炮点剖面变换成任何叠后偏移都能使用的零偏移距数据。炮点—DMO算子是属于空间变量和时间变量性的;因此直接应用算子在计算上是很昂贵的。但对时间和空间座标进行算换后,该算子则变成了时间不变量和空间不变量性质;所以倾角时差可作为傅氏域中的乘法进行有效的计算。因此,炮点倾角时差对于DMO处理后提高剩余速度分析的精度也是一种有用手段。野外数据实例说明,炮点剖面倾角时差法可用来产生叠加剖面,并与用Hale(1984)的固定偏移距剖面的倾角时差法获得的叠加剖面相似。
All known dip-time differences (DMOs) are not integrals The algorithm requires the selection of seismic data from regularly sampled regular offset profiles. However, the dip-time difference method described in this article can be applied directly to shot-point profile recordings and can therefore handle data that can not be selected from regular, fixed-offset profiles. The definition of jet-lag time difference operator is very similar to that of fixed-offset phase profile. Both operators have the same projected impulse response at zero offsets (ie, overlays). Therefore, the same overlay profile can be provided using either the application of a fixed offsets profile or the time difference of tilt in a shot profile. The dip-time difference method transforms the shot profile into zero-offset data that can be used for any post-stack offset. Gunpoint-DMO operators belong to the spatial and temporal variability; therefore direct application of the operators is computationally expensive. However, after time and space coordinates are converted, the operator becomes a time invariant and a space invariant property; therefore, dip time difference can be effectively calculated as multiplication in Fourier domain. Therefore, the jet lag time difference is also a useful measure to improve the accuracy of the remaining velocity analysis after DMO processing. Field data examples show that the shot-dip dip-time difference method can be used to generate a superimposed profile similar to the superimposed profile obtained by the dip-dip method using the fixed offsets profile of Hale (1984).