剖析了含油气系统中生烃子系统、油气运移输导子系统及油气运聚成藏子系统构成及其特点。结果表明：琼东南盆地生烃子系统主要由始新统中深湖相及渐新统煤系烃源岩之生烃灶所构成；油气输导子系统则主要由断裂及裂隙和连续性砂体、不整合、泥底辟、气烟囱等输导体系所构成，控制和制约了油气运聚的主要优势富集区；油气运聚成藏子系统以垂向和侧向运移方式为主，通过输导体系近源或远距离运聚，在圈闭及储盖组合条件极佳的优势区富集成藏。
关键词：含油气系统；生烃；运移输导；成藏；琼东南盆地；南海
中图分类号：P618.130.2 文献标志码：A
Abstract： Based on the theory of petroleum system， the different petroleum systems in Qiongdongnan Basin of the continental margin， the northern South China Sea were comprehensively analyzed by means of regional geology and sedimentary characteristics， history of hydrocarbon expulsion of source rocks， petroleum migration and conduction systems， configuration relationships between petroleum formation and traps， as well as the assemblages and modes of petroleum migration and accumulation. The petroleum system was divided into shallow water petroleum system in the northern depression， deep water petroleum system in the central depression and deep water petroleum system in the southern depression of Qiongdongnan Basin， and 13 petroleum sub-systems further. Because of the obvious difference between petroleum systems and petroleum sub-systems， the composition and characteristics of generation， migration and conduction， migration and accumulation sub-systems were analyzed. The results show that the generation sub-system is composed of Eocene mid-deep lacustrine facies and Oligocene coal series source rock kitchen； the migration and conduction sub-system consists of the pathway systems， including fault， fracture， continuous sand body， unconformity， mud diapir and gas chimney， and controls the main petroleum-bearing advantage region restrictively； the migration and accumulation sub-system is dominated by vertical and lateral migration pattern， and petroleum accumulation in the advantage area under the wonderful condition of trap and reservoir-caprock composition through the proximal or distal migration and accumulation of pathway systems.
Key words： petroleum system； hydrocarbon generation； migration and conduction； accumulation； Qiongdongnan Basin； South China Sea
0 引 言
自20世纪70年代Dow首次提出与油气系统相关的概念[1]以来，含油气系统研究一直是国内外油气领域研究的热点。在理论研究层面，国际上油气地质学界起步较早，Perrodon等首先提出含油气系统概念[2]。Demaison等提出油气系统的成因分类法[3]。Magoon等系统论述并总结了含油气系统，明确指出含油气系统包括成熟的烃源岩及所有已生成的油气藏，并且包括一个油气田赋存所必不可少的一切地质要素及作用[4]。在中国，窦立荣等以气候带为基础，提出含油气超系统的概念及分区[5]。张厚福拟定出油气系统的历史-成因分类法[6]；梁书义等提出油气成藏体系的概念[7]。此外，赵文智等总结并补充研究了国内外含油气系统研究理论、方法、手段等，为含油气系统研究做出了重要贡献[8-10]。在应用实践上，中国很多学者应用含油气系统理论，对不同含油气区和含油气盆地（坳陷）的含油气系统进行了分析与研究[11-20]。王来斌等研究了济阳坳陷车镇凹陷复合含油气系统特征及其演化规律[11]；成永生等对渤海湾盆地乐亭凹陷古近系含油气系统进行了综合研究[12]；方世虎等以准噶尔盆地东部吉木萨尔凹陷为例，探讨了构造演化与含油气系统形成之间的关系[13]；刘华等分析了东营凹陷油-源特征，并划分了含油气系统[14]；何登发等研究了准噶尔盆地石炭系烃源岩分布，并划分了含油气系统[15]；丘东洲等以雪峰山西侧盆山过渡带为例，论述了改造型盆地含油气系统[16]；Wu等初步总结了中国南海北部深水盆地的含油气系统[17]；刘方圆等划分并评价了珠江口盆地恩平凹陷含油气系统[18]。