Abstract: Eastern Baiyun Deepwater Area, located at eastern deepwater area in Baiyun Sag of Zhu II Depression in Pearl River Mouth Basin, is a multiple hydrocarbon generation and accumulation area where three sets of effective source rocks, Wenchang, Enping and Zhuhai formation, early Miocene sand-rich deepwater fan, late Oligocene continental shelf shallow water deltaic reservoir-cap assemblage and structural-lithologic traps, have developed. Based on oil-source correlation of biomarkers and light hydrocarbons data from crude oils, it was concluded that the crude oil and condensate oils in LW3-1 and LH34-2 traps and the condensate oil in LH29-1 gas reservoir mainly generated from Enping Formation source rock in main subsag of Baiyun sag, however, the crude oils from LH29-1 and LH16-2 oil reservoirs mainly generated from Enping Formation source rock in eastern subsag of Baiyun sag, with some contribution of oil generating from Zhuhai Formation source rock. Natural gas is mainly generated by kerogen-cracked gas from Enping Formation source rock in main subsag of Baiyun sag, with the contribution of oil-cracked gas from Wenchang Formation source rock. There are two stages of hydrocarbon accumulation in Eastern Baiyun deepwater area, with the early stage characterized by oil accumulation and late stage by gas and condensate oil. Yuehai period to present is the main accumulation period in Eastern Baiyun deepwater areas. Some oil reservoirs in low uplifts have undergone gas washing. Five fault zones and some fluid diapers developed in Eastern Baiyun deepwater area constitute important vertical migration pathway systems. Regional sandstone, unconformable surface and structural ridge are lateral pathways. They controlled the location of effective source kitchen, the hydrocarbon migration and accumulation together.

Key words: Baiyun sag, deepwater area, oil and gas origin, accumulation characteristics, migration system, source kitchen