基于波动方程重建震源子波的三维全波形反演  

A 3D full waveform inversion method based on reconstructed source wavelet with wave equation

作　　者：梁展源 吴国忱[1] 王玉梅[2] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石化胜利油田物探研究院,山东东营257022

出　　处：《石油地球物理勘探》2017年第6期1200-1207,共8页Oil Geophysical Prospecting

基　　金：国家"973"重大专项(2013CB228604);国家自然科学基金-石油化工基金联合重点项目(U1562215)联合资助

摘　　要：提出一种基于波动方程重建震源子波的三维全波形反演方法,通过提取叠前炮集近炮检距的直达波作为波动方程求解的边界条件,重新求解波动方程,并记录震源点处的时间序列作为地震子波。该方法利用震源波场重建原理模拟震源爆炸沿地表传播的逆过程,在逆推过程中提取近炮检距直达波,避免了折射波、反射波以及潜水波等干扰。该方法只使用模型表层速度,可以有效降低对初始模型的依赖。对三维SEG/EAGE推覆体模型以及实际工区数据的测试结果表明,基于波动方程震源波场重建子波与输入子波只存在相位差异,经过相位调整后,将重建子波用于三维全波形反演,全波形反演速度接近真实速度,特别是在河道处的全波形反演结果更加可靠,观测记录与模拟记录在波形、相位等方面均有较好的对应,验证了算法的可行性与适用性。We propose in this paper a 3D full waveform inversion method based on reconstructed source wavelet with wave equation.We resolve the wave equation with direct waves obtained from near offsets of prestack shot gathers as boundary condi-tions and take time series at the source point as source wavelet.This method uses the principle of seismic source wave field reconstruction to simulate the inverse process of the wave propagation along the surface,and extracts direct waves at near offsets,which avoids the interference such as refraction wave,reflection wave and diving wave.So the method has less dependence on the initial model.For tests,we select the 3D SEG/EAGE overthrust model and field data to analyze the phase difference of 3D seismic wavelet based on the source wavefield reconstruction theory of wave equation.Test results show that there is only phase difference between the reconstructed wavelet and the input wavelet.After the phase adjustment,the reconstructed wavelet is used for the 3D full waveform inversion;the inversion velocity is close to the real one.Results are more reliable for channels.The waveform and phase between observed records and simulated records have also good correspondence,which validates the feasibility and applicability of the proposed method.

关 键 词：地震子波 全波形反演 震源波场重建 波动方程 SEG/EAGE推覆体模型 

分 类 号：P631[天文地球—地质矿产勘探]