琼东南盆地深水区松南低凸起油气复式聚集条件与成藏模式

文章利用钻井、测井、地化以及地震资料,分析研究了南海北部琼东南盆地深水区松南低凸起的油气成藏条件。松南低凸起位于中央坳陷带5大(潜在)富生烃凹陷包围中,烃源充足。中新世早期三亚组大型海底扇、中新世早期—渐新世晚期陵水组生物礁、渐新世早期崖城组扇三角洲—滨海相沉积、前古近系古潜山风化壳等多类型储层发育。生烃凹陷深部沟源断裂、崖城组大型疏导砂体和多条古构造脊构成了本地区主要的垂向+侧向输导体系。多层系多类型大中型构造、构造+岩性圈闭发育。研究表明,多成藏要素的耦合促使松南低凸起成为深水区的独有的复式油气聚集区,其成藏模式为它源-侧向-复式成藏,主要成藏组合是三亚组海底扇、三亚组—陵水组生物礁、前古近系古潜山,成藏主控因素为储层与运移。此结论可为南海北部深水区进一步的勘探提供参考。

The forming conditiong of multiple oil gas accumulation and accumulation model of songnan low uplift in deep-water area of Qiongdongnan Basin

On the basis of drilling,logging,geochemical and seismic data,this paper studies the hydrocarbon accumulation conditions of Songnan low uplift in deep-water area of Qiongdongnan basin,northern South China Sea.Songnan low uplift is located in the central depression Belt and surrounded by five (potential) hydrocarbon rich sags with adequate hydrocarbon source.Multi-type reservoirs occur here,such as the large submarine fans of the early Miocene Sanya formation,the reefs of the Early Miocene-late oligocene Lingshui formation,the fan deltas and coastal sandstone of the early oligocene Yacheng formation and the buried hill weathering crust of pre-tertiary etc.The deep faults that connect source rock in sags,the large sandstone pathway in Yacheng formation and multiple paleo structural ridges constitute the hydrocarbon migration system of this zone.Large and medium structural traps,structural and lithological traps developed in multiple layers.Research shows that the coupling relationship of all accumulation elements makes Songnan low uplift become a unique multiple oil gas accumulation play.And its hydrocarbon accumulation model is neighbour source-lateral migration-multiply formed pool.The main reservoir-forming assemblages are submarine fan of Sanya formation,the reef of Lingshui formation and Sanya formation,and the buried hill of pre-tertiary.And the main controlling factors of hydrocarbon accumulation are reservoir and hydrocarbon migration.The result of this study provides a basis for further exploration of deep-water area in the northern part of the South China Sea.