叠前地震道集AVA多频信息同时反演

Multi-frequency AVA simultaneous inversion for prestack seismic gathers

叠前地震反演在储层预测与流体识别中起到了非常重要的作用,但常规振幅随角度变化(Amplitude Variation with Angle,AVA)三参数反演结果由于分辨率的限制已满足不了隐蔽油气藏勘探的高精度要求。为此,提出了一种综合利用隐含在叠前地震道集中的AVA信息与振幅随频率变化(Amplitude Variation with Frequency,AVF)信息的AVA多频信息同时反演的方法。首先对各入射角地震道集进行谱分解,得到振幅随角度和频率变化(Amplitude Variation with Angle and Frequency,AVAF)三维数据体,然后利用该数据体进行AVA多频信息同时反演,得到高分辨率的岩性参数反演结果。模型和实际资料应用结果表明,叠前AVA多频信息同时反演结果比常规AVA反演具有更高的分辨率,能更精细地刻画砂泥岩薄互层等隐蔽油气藏。

Prestack seismic inversion plays an important role in reservoir prediction and fluid identification. Because of resolution limitation, conventional three-parameter AVA inversion can not satisfy the requirements for the high-precision seismic exploration of subtle reservoirs. We propose a simultaneous inversion method, which utilizes jointly amplitude variation with angle（]kVA） and amplitude variation with frequency（AVF） information. Firstly, by getting the AVF information for a certain incident angle gather with spectral decomposition, the prestack gather is expanded into a 3D AVAF（amplitude variation with angle and frequency） data cube. Then, by muhi-frequency AVA simultaneous inversion on this data cube, high-resolution lithological parameters can be obtained. Model and real data application results indicate that the multi-frequency AVA simultaneous inversion has higher resolution than conventional prestack inversion. More small-scale reservoirs such as thin-beds can be delineated by this method.