Optimising 3D coal seismic imaging with pre-stack depth migration

Pre-stack depth migration (PSDM) is applied to a 3D seismic survey from the Bowen Basin in QLD to improve imaging of shallow coal-seams which suffer from poor signal-to-noise caused by poor statics and velocities. Two different velocity fields are used as initial velocity models. The first is the PSTM velocity field and the second is created based on imaging reflections from the base of weathering. Final seismic images obtained after PSDM velocity updates indicate that the second velocity model is superior in imaging the poor data area and is more representative of depths observed in borehole data. Both initial models yield superior imaging results compared to the time-processing results.