PSDM for improved imaging under seafloor channels - Browse Basin, Australia case study

Abstract

In the Browse Basin, as in many areas of the world, complex seafloor topology can cause problems of seismic imaging. This paper compares ways in which imaging can be improved under seafloor channels, using both time and depth domain processing. In the time domain, to improve on the standard PSTM we applied removable seafloor statics in order to reduce the push down effect under seafloor channels prior to migration. This allows for better event continuity in the seismic imaging below. However this approach does not fully tackle the problem still giving sub-optimal imaging, leaving amplitude shadows, and structural distortions. Only depth domain processing with a migration algorithm that honours the paths of the seismic energy as well as a detailed velocity model can provide good imaging under these seafloor channels, and give confidence in the structural components of the exploration targets in this area. We therefore performed depth velocity model building followed by PSDM, and produced a much improved result.