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Reverse Time Migration with Random Space Shift
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
The classical imaging condition for reverse time migration (RTM) is to cross-correlate the forward propagated source-side wavefield with the backward propagated receiver-side wavefield at zero time- and spatial-lag, under the assumption that an accurate migration velocity model is available to correctly predict the kinematic information of the observed seismic data. When errors are present in the migration velocity model, the conventional RTM image may be defocused. Inspired by the work of the extended RTM with subsurface offset and considering the finite-frequency effects of wave propagation, we propose to introduce a random space shift to the source- and receiver-side wavefield at each time step before applying the cross-correlation imaging condition. The maximum random spatial shift is constrained by the theoretical lateral resolution limit of the half-wavelength after migration. The computational cost of our method is the same as the conventional RTM. Numerical examples on a 2D layered model demonstrate that our method could provide an image with better quality than the conventional RTM even the migration velocity model contains significant errors.