地震波主特性参数的提取

The extraction of main characteristic parameters of seismic wave,

本文根据复信号的能量密度函数及能量在时间一频率域的分布特性,研究了地震反射波群延迟处的瞬时频率、瞬时相位与该波的主频、主相位之间,反射波任意时刻的瞬时频率与该波能量密度函数重心频率的实部之间存在的等价关系。依据这种关系,无需做傅里叶变换,直接利用瞬时参数便可快速提取出表征反射波波形特征的主特性参数(主频率和主相位)。通过正演分析和对实际资料的试算,进一步证实了上述理论的可行性与正确性。文中还给出了对这两种主特性参数剖面的计算方法,指出影响主特性参数计算精度的主要因素在于子波类型的选取、噪音背景及相邻反射波的相干程度。最后简要地叙述了这两种参数剖面在岩性和构造解释中的重要作用。

In accordance with both the energy density function of complex signal and the energy distribution in time-frequency domain, author researched into two equivalent relations: (1) equivalent relation between the instantaneous frequency (or instantaneous phase) of seismic reflection wave group at delay place and the dominant frequency (or dominant phase), and (2) equivalent relation between instantaneous frequency of reflection at any time and the real part of baryecnter frequency of wave-energy density function. In light of the relations, the main characteristic parameters (dominant frequency and dominant phase) that indicate the nature of reflection waveform can be fast obtained by directly using the instantaneous parameters instead of Fourier transform. The feasibility and correctness of this theory were confirmed by forward modeling and the trial computation of real seismic data. The methods for computing the two main characteristic-parameter sections are given. It is pointed out that the main factors influencing the accuracy of the main characteristic parameters are the choice of wavelet type, noise background and the coherence of adjacent reflections. Finally, described briefly is the important role that the two parameter sections play in lithologic and structural interpretations.