【摘要】 常规的地震反演成像分为偏移速度分析与层析成像、叠前深度偏移(角度道集产生)和AVA分析/反演3个重要环节,其中的关键技术是当前勘探地震学中的核心技术。全波形反演(FWI)是理论意义下十分完善的地震波反演成像理论框架。原则上,FWI可以把上述3项常规的反演方法技术合为一体,给出比较理想的反演成像结果。但是,由于叠前地震数据的不完备、地震波正演模拟方法不能很好地模拟实测地震波场、初始模型不够精确、地震子波的未知和空变,使得严格意义下的FWI方法尚不能很好地解决实际问题。通过叠前地震数据和地下介质模型的特征表达,提出把经典的FWI分成透射波层析成像、最小二乘叠前深度偏移成像和反射波层析成像3个线性化反演方法的串联,构成FWI反演成像的实用化流程。针对我国陆上地震数据的特点,指出做好浅层速度模型建立、背景速度模型建立、成像道集层析速度模型建立、最小二乘叠前深度偏移成像、张角及界面倾角道集的产生以及小角度成像道集波阻抗反演,是当前推进FWI反演成像方法技术应用与发展的关键所在。更多还原

【Abstract】 The conventional seismic inversion imaging is divided into migration velocity analysis(MVA)and tomography,prestack migration imaging and AVA analysis/inversion.The key techniques in the three inversion imaging methods are the core technologies of modern exploration seismology.Full waveform inversion(FWI)is a complete theoretical framework of seismic inversion imaging,and which can roll up the three conventional inversion imaging methods into one and give a desired imaging result in principle.However,due to the incompleteness of pre-stack seismic data,imperfectness of forward model,inaccuracy of initial model,unknown and spatial variation of seismic wavelet,the practical problems have not yet been solved with FWI method in the strict sense.In this paper we analyze the existing problems of classical FWI method and propose a practical seismic inversion imaging workflow,that is to divide classic FWI into transmissive wave tomography,LS-PSDM imaging and reflections tomography.Aimed at the features of land seismic data,we point out that the establishment of shallow velocity model,background velocity model,velocity model for CIG tomography,LS-PSDM imaging,generation of the incident angle gather and dip angel gather,impedance inversion by small angel CIG gathers are crucial for the promotion of the application and self-development of FWI technique.更多还原