Common-reflection-surface-based prestack diffraction separation and imaging

Diffraction imaging can lead to high-resolution characterization of small-scale subsurface structures. A key step of diffraction imaging and tomography is diffraction separation and enhancement, especially in the full prestack data volume. In this work, we consider point diffractors and present a robust and fully data-driven workflow for prestack diffraction separation based on wavefront attributes, which are determined using the common-reflectionsurface (CRS) method. In a first of two steps, we apply a zero-offset based extrapolation operator for prestack diffraction separation, which combines the robustness and stability of the zero-offset CRS processing with enhanced resolution and improved illumination of the finite-offset CRS processing. In the second step, when finite-offset diffracted events are separated, we apply a diffraction-based time migration velocity model building which provides high-quality diffraction velocity spectra. Applications of the new workflow to 2D / 3D complex synthetic data confirm the superiority of the prestack diffraction separation over the poststack method as well as the high potential of diffractions for improved time imaging