RTM Imaging Condition Using Impedance Sensitivity Kernel Combined with Poynting Vector

Abstract

Reverse time migration (RTM) using cross-correlation imaging condition is always contaminated by low-spatial-frequency artifacts due the presence of sharp wave-speed constrats in the velocity model. Different thechiques have been used and Laplacian filtering can lead to good results but it migth damage the signal of interest. Recently it has been observed through numerical examples that RTM images obtained using the impedance sensitivity kernel are much less contaminated by low-frequency artifacts. In this work, we are proposing to use the impedance sensitivity kernel instead of the conventional cross-correlation RTM imaging condition to attenuate the low frequency artifacts. Using the impedance sensitivity kernel for the source downgoing wavefield separated by the Poynting vector, we demostrate through syntethic examples that RTM image results preserve well the reflections and attenuate significantly the backscattered low frequency noise.