Tidal sand ridges seismic identification and its application in the Xihu Depression, East China Sea Shelf basin: Enlightenment to hydrocarbon exploration

Tidal sand ridges are the most typical and extensive products of tidal processes and the large-scale layered structures that occur in the coastal area. Although there are abundant sand-riched reservoirs developed in tidal sand ridges, surprising that few people can intuitively identify the distribution in ancient strata. By comparing the seismic microfacies and seismic Root Mean Square Amplitude attribute of high-precision 3-D seismic data, we summarized a new method to identify and describe their superposition and plane distribution. Application examples of the Pingbei Slope Belt in the East China Sea Shelf Basin show the detailed analysis process and the results show that 6 sets of tidal sand ridges have been identified in three intervals of LST, TST, and HST, 5 sets of sand ridges with the same extension direction (342–358°) in LST and HST intervals are obviously affected by tides. This method and application example provides a new meticulous process for tidal sand ridges identification according to the superimposition relationship of seismic microfacies and the plane extension direction of the Root Mean Square Amplitude attribute. The seismic microfacies of it is very easy to be distinguished compared to that of other similar sediments and can accomplish the spatial morphology and parameters characterization of tidal sand ridges in ancient sedimentary strata which buried several kilometers depth in a large-scale area. This method is suitable for most sedimentary basins with tidal background, just need the aid of high-precision 3-D seismic data, and provides practical guidance for the petroleum exploration related to sandstone.