Land near-surface pre-processing for rtm and ls-rtm

Abstract

In the presence of near-surface weathering layers, wave propagation may become complex and accurate velocity estimation can be challenging. As a result, reverse-time migration (RTM) and least-squares (LS)-RTM may provide inaccurate images of low-resolution contaminated with artifacts. Therefore, prior data conditioning with near-surface correction is routinely applied on land data. However, there is an associated risk that this process may also remove details from the subsurface model or may not fully account for the near-surface effects leading to poor and erroneous image. We propose to utilize a data-driven rank-based approach that does not require a velocity model to mitigate the effects of rapid changes of surface-elevation and properties of the weathering layers prior to RTM and LS-RTM. We demonstrate that this pre-processing step can restore the high-resolution information and reduce the artifacts of the migrated image while preserving the subsurface structure.