利用特色叠前深度偏移技术消除崎岖海底影响——以珠江口盆地番禺—流花地区应用为例

叠前深度偏移技术可有效地进行复杂构造成像,针对不同的地质条件,需要应用不同的处理技术。针对陆架坡折带崎岖海底造成的地震成像差、构造畸变等问题,选择使用了如下叠前深度偏移技术:通过海平面叠前深度偏移技术得到精确的海底成像;通过约束速度反演、加入断层控制建立初始速度模型;采用百分比扫描速度分析对速度模型进行迭代修改,进而快速得到较为收敛的速度体;在此基础上再采用Kirchhoff积分法进行偏移。在珠江口盆地番禺—流花地区应用上述技术,基本消除了崎岖海底对下伏地层的影响,改善了断层和地层成像,并落实了该地区的构造圈闭。

Special Pre-stack Depth Migration Technology Removing Influences of Rough Seafloor:An Example of Application in Panyu-Liuhua Sea Area,Pearl River Mouth Basin

The Pre-stack depth migration(PSDM) technology is recognized as the effective way to resolve the seismic imaging of complex geological structures.Different special PSDM technology is needed according to different geological settings.The seafloor is rough with a series of deep canyons and the seismic imaging underlying is distorted.To solve these problems,the special PSDM technologies are used.The pre-stack depth migration from the sea surface is used to get the accurate seafloor images.The initial velocity model is made with the controlled velocity inversion(CVI) technology and the main faults are added to the model.Then a velocity scanning analysis is introduced and the velocity model converges quickly.The Kirchhoff integral migration method is used to perform the PSDM.These researches were applied in Panyu-Liuhua region in Pearl River Mouth Basin and got achievement,which reveals that the influences of rough seafloor are essentially removed and the imaging of faults and seismic layers is improved as a consequence of some structural traps validated.