The deep-water zone in the Baiyun Sag

Pearl River Mouth Basin

is an important prospect area for oil and gas exploration in the northern South China Sea

but the understanding of the system tracts' composition and the depositional evolution process of the deep-water fans is still to be strengthened. Based on the comprehensive analysis of 3-D seismic profile

well logging and drilling data and plane properties

we discussed the evidences to identify FSST and LST

described and compared the sedimentary facies distribution characteristics and spatio-temporal evolution processes of the deep-water fans in the two system tracts. The result suggests that the fan in FSST is a small tongue-shaped fan

supplied by single sandy source vertically

whereas the fan in LST is a large irregular superposed fan with multi-line sources of mixed sand and mud

getting rid of major provenance supply from the delta. During the transformation from the former to the latter with multi-factors coupling

we speculate that such synthetic factors as sufficient sediment supply at the continental shelf break and relative sea level changes

function to provide a fundamental background;simultaneously

the strong coastal currents from southwest to northeast can be a favorable factor for the transformation.