High-Resolution Full-Waveform Inversion Focused on Target Area by Using the Visco-Acoustic Redatumed Data

The inherent viscosity of the subsurface medium can significantly affect the characteristics of seismic wave propagation, specifically including amplitude attenuation and phase distortion. Full-waveform inversion (FWI) is a high-resolution imaging method for recovering the subsurface medium properties by fully utilizing the waveform information of seismic data. The influence of the viscosity in the subsurface is often neglected by the conventional FWI method, leading to reduced resolution and accuracy of the inversion result. Besides, the conventional FWI method aims to estimate the subsurface parameter model of the entire survey area, which often demands significant computational resources. Target-oriented FWI allows us to focus the high-resolution inversion on a specific region of interest, thus improving the computational efficiency. Here, we develop the target-oriented FWI with a visco-acoustic redatuming method to characterize a target area underlying a visco-acoustic overburden model with high resolution. We first retrieve the virtual reflection data at the datum level by suppressing the influence of the visco-acoustic overburden on the observed seismic data. The retrieved reflection data is then directly used to invert for the target zone of interest. In the numerical example section, we use a three-layer model and the Marmousi2 model to prove the effectiveness of the proposed method and analyze the influence of the viscosity on the redatuming and the target inversion result. The test result on the field data demonstrates the feasibility and practicality of the proposed method.