融合点扩散函数的预条件黏声最小二乘逆时偏移

Preconditioned visco-acoustic least-squares reverse time migration integrated with point spread function

在传统黏声最小二乘逆时偏移(Q-LSRTM)中,用于反传残差数据的伴随Q传播算子也是衰减的,因此导致其成像分辨率较低。为了改善Q-LSRTM的低分辨率问题,基于点扩散函数(PSF)构建黏声去模糊滤波器,然后将其作为Q-LSRTM迭代过程中的预条件化因子,最终实现高分辨的衰减补偿偏移,因此称为预条件Q-LSRTM。模型测试表明,预条件Q-LSRTM能获得更高的分辨率、更均衡的振幅以及更快的收敛速度。Q值偏移模型的敏感性测试表明,与Q-LSRTM相似,为了显著改善成像效果,预条件Q-LSRTM也需要相对精确的Q值模型和速度模型。

In conventional visco-acoustic least-squares reverse time migration(Q-LSRTM),the adjoint Q propagators used for backward propagating residual data are also attenuative.Thus,the inverted images from Q-LSRTM are often observed to have lower resolution.To increase the resolution of QLSRTM,a preconditioned visco-acoustic leastsquare reverse time migration is put forward in this paper.The preconditioner is built with viscoa-coustic deblurring filters based on visco-acoustic point spread function.Model tests show that the preconditioned Q-LSRTM can produce images with higher resolution and more balanced amplitudes with faster convergence rate.With sensitivity tests of migration Q model,as the same case of Q-LSRTM,preconditioned Q-LSRTM also need a fairly accurate estimation of migration Q model in order to obtain noticeable improvements in the image quality,meanwhile a fairly accurate velocity model is also needed.