Preserved-Amplitude Angle Domain Migration by Shot-Receiver Wavefield Continuation
Résumé
We present preserved-amplitude downward continuation migration formulas in the aperture angle domain. our approach is based on shot-receiver wavefield continuation. Since source and receiver points are close to the image point, a local homogeneous reference velocity can be approximated after redatuming. We analyze this approach in the framework of linearized inversion of Kirchhoff and Born approximations. From our analysis, preserved-amplitude Kirchhoff and Born inverse formulas can be derived for 2D case. They involve slant stacks of filtered redatumed offset domain common image gathers followed by the application of the appropriate weighting factors. For the numerical implementation of these formulas, we develop an algorithm based on true amplitude version of the one-way paraxial approximation. Finally, we demonstrate the relevance of our approach with a set of applications on synthetic datasets and compare our results with those obtained on the Marmousi model multi-arrival ray-based preserved-amplitude migration. While results are similar, we observe that our results are less affected by artefacts.