地震子波外推方法研究

Study on seismic wavelet extrapolation method

关键词:  地震子波  离散反演  外推  相位  小波时频分析

Key words:  seismic wavelet  discrete inversion  extrapolation  phase  wavelet time frequency analysis

摘要:

根据离散反演理论,综合测井和地震资料，充分考虑了地震子波的振幅特点和相位特点,给出了精确计算井旁 地震子波的方法。在此基础上,针对测井与地震资料及地层的地质特点,提出了 3种无井地震道处地震子波的外推 方法,即反距离内插法、相位内插法和虚拟井法。其中反距离内插法是直接按照距离内插井旁子波;相位内插法则 只内插井旁子波的相位,无井地震道处的振幅谱通过邻近的地震资料求出;虚拟井法是通过地震层序分析方法，由 小波时频分析求出无井地震道处的虚拟反射系数后,进而得到无井地震道处的地震子波。介绍了各种方法的实现 步骤，并给出了应用实例。结果表明,尽管各种方法计算的子波〒同，但子波的变化是连续的。

Abstract:

According to the theory of discrete inversion，an accurate method of seismic wavelet extraction was proposed by using well log data and seismic data. The features of amplitude spectrum and phase spectrum of seismic wavelet were considered in the method. Integrating seismic data and geological data，three seismic wavelet extrapolation methods were presented， that is, inverse distance interpolation method, phase interpolation method and pseudo well log method. The seismic wavelets in well location were interpolated according to the inverse distance in the first method. Only the phase spectrums of the seismic wavelets in well location were interpolated in the second method，and the amplitude spectrums were computed by seismic data. While in the third method, wavelet time frequency distribution technique was used to compute the virtual reflection factor and the seismic wavelet. Detailed process for realizing these methods and examples weie illustrated. The Tesults show that the variances of the wavelets are continuous for all kinds of methods，though different wavelets are extracted.