Waveform inversion based on least-squares reverse time migration (LSRTM) usually involves Born modeling, which models the primary-only data. As a result, the inversion process handles only primaries and corresponding multiple elimination preprocessing of the input data is required prior to imaging and inversion. Otherwise, multiples left in the input data are mapped as false reflectors, also known as crosstalk, in the final image. At the same time, the developed full-wavefield migration (FWM) methodology can handle internal multiples in an inversion-based imaging process. However, because it is based on the framework of the one-way wave equation, it cannot image dips close to and beyond 90°. Therefore, we have aimed at upgrading the LSRTM framework by bringing in the functionality of FWM to handle internal multiples. We inject the secondary source term, as used in the original formulation of FWM, to define a wavefield relationship that allows modeling multiple scattering via reflectivity. The secondary source term is based on the estimated reflectivity and can be injected into the pressure component when simulating the two-way wave equation using finite-difference modeling. We use this modified forward model for estimating the reflectivity model in an FWM-type manner and validate the method on synthetic and field data containing visible internal multiples.

中文翻译：

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全波场最小二乘逆时偏移

基于最小二乘逆时偏移 (LSRTM) 的波形反演通常涉及 Born 建模，该建模对原始数据进行建模。因此，反演过程仅处理原色，并且在成像和反演之前需要对输入数据进行相应的多次消除预处理。否则，留在输入数据中的倍数会在最终图像中被映射为假反射器，也称为串扰。同时，开发的全波场偏移 (FWM) 方法可以在基于反演的成像过程中处理内部多次波。然而，由于它是基于单向波动方程的框架，它不能对接近和超过 90°的倾角进行成像。因此，我们的目标是通过引入 FWM 处理内部倍数的功能来升级 LSRTM 框架。我们注入了 FWM 原始公式中使用的二次源项，以定义波场关系，允许通过反射率对多次散射进行建模。二次源项基于估计的反射率，可以在使用有限差分模型模拟双向波动方程时注入压力分量。我们使用这种改进的前向模型以 FWM 类型的方式估计反射率模型，并在包含可见内部多次波的合成和现场数据上验证该方法。二次源项基于估计的反射率，可以在使用有限差分模型模拟双向波动方程时注入压力分量。我们使用这种改进的前向模型以 FWM 类型的方式估计反射率模型，并在包含可见内部多次波的合成和现场数据上验证该方法。二次源项基于估计的反射率，可以在使用有限差分模型模拟双向波动方程时注入压力分量。我们使用这种改进的前向模型以 FWM 类型的方式估计反射率模型，并在包含可见内部多次波的合成和现场数据上验证该方法。