宽频地震处理技术振幅保真性分析与应用

Amplitude Preserving Analysis and Application of Broadband Seismic Processing Technique

研究区位于珠江口盆地恩平凹陷北部隆起带,近几年在中浅层相继获得多个商业性油田发现,特点是目的层砂体厚度普遍小于15 m,主力油层通常具有“亮点”振幅异常和第三类AVO特征。老地震资料低频成分缺乏,分辨率不足,并且AVO特征与钻井吻合度低,难以满足中浅层小断层精细解释、以及储层和流体研究的需求,针对如上问题,开展了以鬼波压制为核心的宽频地震处理。与老资料相比,本次宽频处理数据分辨率和信噪比显著提高,小断层得到了很好的刻画,深层和基底成像信噪比进一步提升,井震标定效果、井旁道AVO特征与钻井的吻合度更好。基于宽频处理成果和老成果分别提取主力层的振幅属性和吸收衰减属性,对比表明,宽频处理成果预测的储层展布和含油气特征更合理,进一步证实了以鬼波压制为核心的宽频地震处理技术在储层和流体研究方面的可靠性和优越性。

In recent years,a number of commercial oil fields have been found in the middle and shallow layers of the study area(located in the northern uplift belt of Enping sag in the Pearl River Estuary Basin).The thickness of sand bodies in the target layer is generally less than 15m,and the main oil layer normally shows“bright spot”and the type 3 AVO.Due to the lack of low-frequency components,insufficient resolution,low coincidence between AVO characteristics and drilling,the previous seismic data can hardly meet the needs of fine interpretation of small faults in the middle and shallow layers and reservoir and fluid research.Considering the problems above,the broadband seismic processing technique centered on ghost wave suppressing is employed,which can effectively widen the frequency band of the seismic data.In comparison with the former seismic data,the broadband data processing has significantly improved the resolution and the signal-to-noise ratio.Small faults are well characterized,the imaging signal-to-noise ratio of deep layers and the basement has been further promoted as well.The similarity of well-seismic calibration is higher and AVO characteristics are more consistent with the drilling results.The amplitude and absorption attenuation properties are extracted respectively from the broadband seismic processing results and former data results of main objective layers.The comparison of the two results shows that the reservoir distribution and hydrocarbon bearing characteristics predicted by broadband seismic processing results are more reasonable,which further confirms the reliability and superiority of the broadband seismic processing technique centered on ghost wave suppressing in respect of reservoir characterization and fluid prediction.