南海北部珠江口盆地西区文昌B凹陷油气运聚成藏模式

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

以南海北部珠江口盆地西部文昌B凹陷构造沉积演化分析为基础,以不同构造带和含油气层系油气成藏特征为依据,将文昌B凹陷及周缘油气运聚成藏模式划分为南部陡坡带扇三角洲骨架砂岩近源垂向运移的古近系断层圈闭聚集成藏模式、南部陡坡带断裂+砂岩垂向运移的新近系背斜圈闭聚集成藏模式、北部缓坡带骨架砂岩近源侧向运移的古近系地层超覆圈闭聚集成藏模式及北部凸起区骨架砂岩+断裂长距离侧向运移的新近系背斜圈闭聚集成藏模式4种类型。在此基础上进一步分析了不同类型油气成藏模式的"源-汇-聚"等油气运聚成藏特征,指出了不同类型油气藏形成与分布的主控因素。同时,根据不同类型油气藏分布富集规律,对文昌B凹陷及周缘有利勘探目标进行了评价预测并经钻探获得了证实,取得了较好勘探成效。

Upon tectonic and sedimentary evolution, there are four kinds of hydrocarbon accumulation pat- terns 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.