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根据地震剖面上地震波的视速度,可以用速度滤波的方法把地震剖面上的相干能量区分开来。“切割滤波”是在时间—距离域用有限多道算子实现的。为了简化褶积运算,所需要的典型的算子是:长度为21个时间点,一共包括12道,其压制水平应小于理想的响应函数,约在20分贝以下。虽然“切割滤波”(扇形滤波)可应用于迭加剖面,但我们认为,在频率—波数域里利用未迭加资料作速度滤波也许更为合适。只要在处理数据采集时采取某些相应的措施,这种方法的优点就可以得到比较好的发挥。 (1)输出道数等于输入道数。 (2)更接近于理想的滤波响应。 (3)不需要预先计算滤波系数。 (4)滤波的实现是用简单的乘法。 (5)因为在频率—波数域里采用了数据的相互配合检验,这就容许在滤波器响应的设计上有较大的灵活性。 (6)由于在时间—距离域里采用了群速度,因此,在频率—波数域中,就可以对相速度及假频程度得出更正确的估价。 (7)在频率—波数空间可对数据作其他一些波场运算。频率—波数域的速度滤波,对英国国家煤碳部所记录到的高分辨率、单检波器数据来说,具有特别重要的意义。本文给出了有关这方面资料的实际例子。
According to the apparent velocity of seismic waves on the seismic section, the coherent energy on the seismic section can be distinguished by velocity filtering. The “cut filter” is implemented in the time-distance domain with a finite number of operators. In order to simplify the convolution operation, the typical operators needed are: A total length of 21 time points, including a total of 12, the suppression level should be less than the ideal response function, about 20 dB below. Although “cut filter” (fan-shaped filter) can be applied to the superposed profile, we think it may be more appropriate to use the non-added data for velocity filtering in frequency-wave number domain. As long as the appropriate measures taken to deal with data collection, the advantages of this method can be better played. (1) The number of output channels equals the number of input channels. (2) is closer to the ideal filter response. (3) There is no need to pre-calculate the filter coefficient. (4) The realization of filtering is to use simple multiplication. (5) This allows for greater flexibility in the design of the filter response because of the interoperability testing of the data in the frequency-wavenumber domain. (6) Since the group velocity is used in the time-distance domain, a more accurate estimate of the phase velocity and the degree of aliasing can be derived in the frequency-wavenumber domain. (7) Some other wavefield operations on the data are possible in frequency-wavenumber space. Velocity-wave-speed domain filtering is of particular importance for the high-resolution, single-detector data recorded by the British Ministry of Coal. This article gives a practical example of this information.