Shelf margin delta is characterized by high-quality combination of source rocks

reservoirs and caps

and multiple trap types.Based on genetic styles

it can be classified into three types:provenance-dominated type

sea level-dominated type and hybrid type.During the relative quiescence period of sea-level

large amount of sediments are transported to the continental slope by rivers

making the shelf break gradually move seaward.Then shelf margin delta deposits could be formed at the shelf break and continental slope.Moreover

during period with relative stable sediment supply

the lowering of sea level to the shelf break also can transport large amount of sediments crossing broad continental shelf to shelf break

forming shelf margin delta deposits.These characteristics make shelf margin delta system identifiable in sequence stratigraphic framework.For example

shelf margin delta often shows large 'S' progradational reflection structure on seismic profiles

and the thickness between top surface and bottom surface can reaches up to hundreds of meters

much thicker than that within continental shelf.Moreover

the shelf margin delta usually occurs in lowstand system tract and is characterized by landward and seaward slope wedges.Based on integrated analysis of recent well logs and high-resolution 3D seismic data from Baiyun sag

a series of Oligocene-Miocene shelf margin deltas were identified in the Zhuhai Formation and Zhujiang Formation

and some unique deep-water reservoir systems were also recognized in the shelf break.These understandings will be helpful to future deep-water exploration.