基于地震叠前大角度道集的调谐压制提高分辨率的方法

地震叠前成像的叠加数据受大角度道集干涉调谐作用影响,子波特征模糊、分辨率降低。对此,利用正演模拟首先明确大角度数据干涉的形成机理,即随着入射角的增大,地层时间厚度减小,导致数据发生干涉调谐效应。在此基础上,进一步分析地层顶底干涉的陷频周期条件、正演模拟陷频和假陷频特征,明确了提高分辨率应在资料的原始频带内实施。依据叠前共成像道集的同源性理论,通过构建叠前大角度数据与小角度数据的匹配关系,求解匹配因子用以压制大角度数据的调谐效应,从而提高地震叠前成像的叠加数据的分辨率。在胜利油田CD地区的实际应用表明,该方法能有效提高大角度数据的分辨率,处理的成像道集叠加后分辨率得到了明显提高。

The method of resolution improvement through tuning suppression based on large angle pre-stack seismic data

The features of wavelets extracted are vague and the ability of solving them is low because the stacked data is affected by interference tuning during seismic data imaging in pre-stack. The formation mechanism of the large angle data interference is made clearly through forward modeling, which is the formation time thickness decreases with the increase of the incidence angle which leads to the interference of the data. It is certified that the data resolution should be enhanced within original frequency band through analysis of conditions generating cyclical notch frequency at the top and bottom bed and modeling pseudo - notch frequency characteristics in forward. Based on the homology of the prestack common image gathers, the matching relationship between the big angle data and the small angle data is built to extract match factors for suppressing tuning effect due to large angle data. As a result the resolution of stacked data could be improved during seismic data imaging. Its application to CD area shows that the resolution of large angle data can be effectively improved through the method, and the resolution of the processed image gathers is improved obviously.