南海北部多幕裂陷作用与含油气系统

南海北部的断陷盆地经历了早第三纪裂谷期和晚第三纪及第四纪裂后期二个演化时期,具多幕裂陷作用.构造与沉积的耦合作用,使盆地的演化具有多个阶段,包括构造地层序列的多幕性和各幕沉积充填样式的不同,以及因此形成的不同时期的烃源岩,组成了多个含油气系统;同时,断裂的多次活动,使早期含油气系统中已成藏的油气再次运移并再次聚集成藏.珠江口盆地珠三坳陷裂谷期可分为三个演化幕,而晚始新世末的一次盆缘张断事件造成了Ⅱ、Ⅲ幕之间沉降中心的迁移,发育了不同类型的古湖泊,形成了不同有机质类型的烃源岩,组成了多个含油气系统.裂后期的裂陷幕与油气的再次运移和再次成藏密切相关.

MULTISTAGE RIFTING AND PETROLEUM SYSTEMS IN THE NORTHPART OF SOUTH CHINA SEA

Rifting basins in the north part of South China Sea have experienced two evolution stages:rifting stage in the early Tertiary and postrifting stage in the late Tertiary and Quaternary.Due to coupled sedimentation and multistage rifting,the basins were infilled with recyclical tectono stratigraph successions,including a series of source rocks,which constitute more than one petroleum systems.Meanwhile,it is an important process for hydrocarbon accumulation that the remigration and retrap of oil and gas caused by reactivities of fault system.There are three evolution episodics in the rift stage of Zhu Ⅲ subbasin in Pearl River Mouth Basin,in which an event of basin boundary faulting occurred at the end of late Eocene that made the subsidence center migrated,different type of paleolakes developed,multitypes of source rocks and a series petroleum systems formed.Faulting episodic in the postrift stage,however,were closely related to the remigration and retrap of oil and gas.