薄互层地震成像中高分辨率处理方法

地震子波在叠前时间偏移前、偏移过程中以及偏移后具有不同特性和非稳态性,使得基于子波压缩原理的反褶积和基于绕射叠加原理的叠前时间偏移不能有效地提高薄互层地震分辨率.本文基于叠前时间偏移前后以及偏移过程中地震子波频率特性的分析,联合三种高分辨率处理方法对薄互层进行成像,即偏移前CMP道集应用反Q滤波补偿高频衰减、偏移过程中应用最优加权Kirchhoff叠前时间偏移降低高频损失、偏移后在CRP道集上应用子波调谐反褶积拓展频带.数值分析和实例证明,本文采用的三种高分辨率处理方法是必要的,对刻画薄互层厚度与边界能够取得好的效果,利于后续的岩性储层预测与AVO/AVP/AVA反演.

High-resolution processing methods of thin interbeds imaging

Owing to different characteristics and nonstationarity of seismic wavelet before, during and after pre-stack time migration (PSTM), conventional deconvolution centering on wavelet's compression and PSTM based on diffraction summation fail to enhance seismic resolution of thin interbeds imaging. According to different attributes of wavelet's frequency in different processing stages, three sequential methods for improving thin interbeds imaging are presented in this paper including the inverse Q filtering on CMP gathers for compensating high frequencies, optimal weighted Kirchhoff PSTM for reducing high-frequency decay and wavelet harmonizer deconvolution on CRP gathers for consistent processing and broadening frequency-band. A model and a case study proved that the processing methods are very necessary and useful for determining thickness and border of thin interbeds and beneficial for subsequent reservoir predictions and AVO/AVP/AVA inversions.