Application of PSDM imaging technology based on floating datum of approximate true surface

The conventional CMP floating datum processing method based on horizontal surface assumption is not suitable for the imaging of the complex tectonic area in the Southern Junggar Thrust Belt.This paper selects the floating datum of approximate true surface as the processing datum in both the time domain and the depth domain.The pre-stack time-domain preprocessing includes selecting optimal the near-surface bottom boundary,the static correction for surface consistency of approximate true surface,surface-consistent DSR NMO velocity analysis,and residual static correction,in order to maintain the consistency of the process and parameters from the time-domain preprocessing to pre-stack depth migration (PSDM).The selection of the floating datum makes the wavefield travel time closer to the actual travel path and realizes higher imaging precision and accurate geological structure.