First-order multiples imaging aided by water bottom

Abstract Surface-related multiples frequently propagate into the subsurface and contain abundant information on small reflection angles. Compared with the conventional migration of primaries, migration of multiples offers complementary illumination and a higher vertical resolution. However, crosstalk artifacts caused by unrelated multiples during reverse time migration (RTM) using multiples severely degrade the reliability and interpretation of the final migration images. Therefore, we proposed RTM using first-order receiver-side water-bottom-related multiples for eliminating crosstalk artifacts and enhancing vertical resolution. We first backward propagate the first-order receiver-side water-bottom-related multiples using a water-layer model, followed by saving the upper boundary wavefield. Then we produce the source wavefield using a seismic wavelet and the receiver wavefield by back-extrapolating the saved boundary. Finally, the cross-correlation imaging condition is applied to generate the final image. This method transforms the receiver-side multiples into primaries, followed by the conventional migration processing procedures. Numerical examples using synthetic datasets demonstrate that our method significantly enhances the imaging quality by eliminating crosstalk artifacts and improving the resolution.