A Wavefield-separation-based Elastic Least Squares Reverse Time Migration
B. Gu, Z. Li and J. Han
Event name: 80th EAGE Conference and Exhibition 2018
Session: Seismic Imaging - Theory I
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 1.54Mb )
Price: € 20
Compared with the elastic reverse time migration (ERTM), ELSRTM can produce images with higher spatial resolution, more balanced amplitudes and fewer artifacts. However, the crosstalk between compressional (P-) and shear (S-) waves can significantly degrade the imaging quality of ELSRTM. We developed an ELSRTM method to suppress the crosstalk artifacts. This method includes three crucial points. The first is that both the forward and backward wavefield are extrapolated based on the separated elastic velocity-stress equation of P- and S-waves. The second is that the separated vector P- and S-wave residuals are migrated to form reflectivity images of Lamé constants λ and μ independently. The third is that the reflectivity images of λ and μ are obtained by the vector P-wave wavefields achieved in the backward extrapolation of the separated vector P-wave residuals and the vector S-wave wavefields achieved in the backward extrapolation of the separated vector S-wave residuals respectively. Numerical tests with synthetic data demonstrate that our ELSRTM method can produce images free of the crosstalk artifacts.