HYDROCARBON ACCUMULATION PATTERN OF WENCHANG B SAG, WESTERN PEARL RIVER MOUTH BASIN IN THE NORTHERN SOUTH CHINA SEA

Upon tectonic and sedimentary evolution, there are four kinds of hydrocarbon accumulation patterns in the Wenchang Sag of the Pearl River Mouth Basin. ① In the southern steep slope belt, hydrocarbon migrated vertically through deltaic sands and accumulated in the Paleogene fault-structures. ② In the southern steep slope belt, hydrocarbon migrated vertically through sands and fault and accumulated in the Neogene anticline structures. ③ In the northern gentle slope belt, hydrocarbon migrated laterally through sands and accumulate in the Paleogene stratigraphic traps. ④ In the northern high area, hydrocarbon migrated laterally for a long distance through sand and fault and accumulated in the Neogene anticline traps. The characteristics of each hydrocarbon accumulation pattern, which includes source, migration, accumulation and so on, are analyzed and the main controlling factors discussed. And the prediction of favorable traps have been proved by drilling.