应用小波尺度域地震波衰减属性检测气层

本文从小波域瞬时参数和尺度能量方程出发,提出小波尺度域的能量属性和瞬时属性在一定的尺度范围内可以表征地震信号的衰减特征,并把它们定义为小波尺度域地震波衰减属性。其含义为：①实际地震信号的尺度能量在极值点尺度达到最大,从该尺度起的“带通”范围内,随尺度的减小,反射信号的尺度能量呈指数降低;②由极值点尺度起向小尺度方向的“带通”区域内所计算的尺度能量称为地震波尺度能量衰减属性,相应尺度的瞬时参数剖面也归结为地震波小渡尺度域衰减属性范畴。理论模型研究和实例分析表明,小波衰减属性较常规的瞬时振幅属性对气层的敏感性强。当检测薄的含气地层或地震记录中含噪声时。小波衰减属性的检测效果明显好于常规的瞬时振幅属性。

Detection of Gas Reservoir by Using Seismic Attenuation Attributes in Wavelet-Scale Domain

Starting from the equation of instantaneous parameters and scale energy in wavelet domain,the paper considered that the energy attribute and 'instantaneous attributes in wavelet scale domain can represent attenuation character of seismic signal in a certain scale scope and defined them as attenuation attributes of seismic wave in wavelet scale domain. Its meanings are as follows:(1)the scale of scale energy of real seismic signal can reach maximum at extreme point and scale energy of reflected signal exponentially decreases with the decrease of scale within a " bandpass " scope starting at that scale; (2) the scale energy computed within the " bandpass " area along the small-scale direction starting in the scale at extreme point is called as energy-attenuated attribute of seismic wave scale, the instantaneous parameters sections in relative scale are also classified as the category of attenuation attribute in wavelet scale of seismic wave. The theoretical study and analysis of cases showed that the attenuation attribute of wavelet is more sensitive to gas reservoir by comparison with ordinary instantaneous amplitude attribute, the detective effects by attenuation attribute of wavelet is obviously better than that by ordinary instantaneous amplitude attribute when detecting the thin gas-bearing beds or on noise-bearing seismic records.