地震复谱分解技术及其在烃类检测中的应用  

Seismic complex spectral decomposition and its application on hydrocarbon detection

作　　者：韩利 刘春成 张益明 韩立国[2] 叶云飞 

机构地区：[1]中海油研究总院,北京100028 [2]吉林大学,长春130026

出　　处：《地球物理学报》2016年第3期1095-1101,共7页Chinese Journal of Geophysics

基　　金：国家重大专项子课题(2011ZX05025-001-07)资助

摘　　要：谱分解技术在地震解释领域已得到广泛应用,但常用的谱分解方法存在两方面的不足.一是时间分辨率低,难以对薄层进行刻画;二是在烃类检测中多解性强,难以区分流体类型.为了改善该问题,本文提出一种基于地震复谱分解技术的烃类检测方法.复谱分解是指用一个包含多个不同频率Ricker子波的复子波库对地震道进行分解,从而得到时变子波频率和相位信息的过程.借助稀疏反演技术复谱分解可以获得高分辨率的时频能量谱和时频相位谱.本文首先通过拟合算例验证了复谱分解方法刻画薄层的能力以及求取子波频率和相位的准确性.然后利用基于Kelvin-Voigt模型的黏弹波动方程数值模拟对衰减引起子波相位改变的原因进行了分析.最后通过实际资料应用展示了本文方法在储层预测中的高时间分辨率优势,验证了利用子波相位信息识别气藏的有效性.Spectral decomposition techniques have been widely used in seismic interpretation.However,the traditional methods have two limitations,low time resolution and uncertainty in predicting fluid types.In this paper,a seismic complex spectral decomposition technique is developed to achieve a much higher resolution in time-frequency distributions via inversion strategy and to reduce the uncertainty in hydrocarbon detection with the extracted wavelet phase information.The time-varying wavelet frequency and phase information are obtained by decomposing the seismic trace using a wavelet library composed of a number of complex Ricker wavelets with different dominant frequencies and zero phase.This process is referred to as the seismic complex decomposition.The Synthetic examples show the ability of the proposed method to distinguish closely positioned wavelets and the accuracy to extract the wavelet frequency and phase information from the seismic data.The causes of wavelet phase change due to attenuation are studied by using the viscoelastic wave equation modelling which is based on the Kelvin-Voigt model.The result demonstrates that the phase change not only occurs in the process of wave propagating,but also occurs at theinterface where existing impedance or attenuation contrast.The impedance contrast only changes the polarity of the wave,while the attenuation contrast is the key reason that rotates the wavelet phase.The gas reservoir has high attenuation property,so that it could be predicted via the wavelet phase change information.The real data example demonstrates the high time resolution of the proposed method in reservoir prediction and the successful application of the phase information in distinguishing gas saturated layers and water saturated layers.

关 键 词：复谱分解 高分辨率 时频谱 时频相位谱 烃类检测 

分 类 号：P631[天文地球—地质矿产勘探]