Elastic reverse time migration in VTI media based on the acoustic wave equations

摘要

Elastic reverse time migration, as a predominant technique for imaging complex structure by multicomponent elastic seismic data, potentially offers a great improvement over conventional acoustic reverse time migration to create some special medium properties. Since anisotropy widely exists in the earth, neglecting anisotropy effect will result in some inaccurate results during processing the seismic data. It is therefore important to take anisotropy into account and correct the anisotropy effect during elastic reverse time migration. Based on previous framework of elastic reverse time migration in isotropic media, we have developed a new elastic reverse time migration method to correct the anisotropy effect. Our new method is based on the acoustic VTI wave equations for assisting the elastic wavefield separation in VTI media to reduce crosstalk artifacts between different wave modes. Moreover, our proposed method uses the vector imaging conditions and doesn't involve polarity reversal problem in converted-wave image. The synthetic examples reveal that our new elastic reverse time migration scheme can correct the anisotropy effect effectively, obtain uncontaminated and meaningful images and generate higher quality images than the conventional isotropy elastic reverse time migration. (C) 2019 Elsevier B.V. All rights reserved.