高精度地震资料叠前逆时偏移模型分析与应用

High precision seismic data pre-stack reverse-time migration model analysis and application

为了满足松辽盆地中浅层地质目标精细刻画的要求,开展了高精度叠前逆时偏移技术的探索应用研究。首先采用层状介质模型合成了逆时偏移脉冲响应,分析了地震波数值频散现象在不同空间方向的传播效应;接着,采用国际标准的TTI介质模型,开展了不同逆时偏移参数对地震成像结果的影响分析;最后,在松辽盆地PN地区,对高信噪比地震资料进行了高精度逆时偏移处理实践。研究结果表明,逆时偏移参数在纵向上必须满足数值频散关系,而在横向上可以适当放宽数值频散关系的约束,同时,通过提高逆时偏移频率参数,丰富了参与逆时成像的波场信息,从而提高了最终逆时偏移结果的信噪比和纵横向的分辨能力,这在高精度地震资料叠前逆时成像处理和精细地质构造目标刻画等方面具有一定的推广应用价值。

In order to meet the requirement of refining geologic target in shallow layer of Songliao Basin, exploring research on high precision pre-stack reverse-time migration technology was carried out. Firstly, the reverse-time migration impulse response with layered medium model was simulated to analyze the seismic wave numerical dispersion phenomena’s propagating effect spread along different spatial directions. Secondly, international standard TTI medium model was used to do the analysis of different re？verse-time migration parameters on the seismic migration results. Finally, the high precision pre-stack reverse-time migration technology was applied in the high SNR seismic data of PN area in Songliao Basin. Results show that, the vertical reverse-time mi？gration parameters must meet numerical dispersion relation, while the horizontal reverse-time migration parameters can be appro？priate to relax the constraint. Meanwhile, the improvement of the frequency parameter can increase the seismic wave field informa？tion involved in reverse time imaging to improve the SNR and resolution of the final reverse-time migration results, which has cer？tain application value in many aspects, such as high precision seismic wave pre-stack reverse-time migration, fine geological struc？ture target characterization, and so on.