北部湾盆地迈陈凹陷东部地区油气成藏特征

Characteristics of hydrocarbon pooling in the east of the Maichen sag of the Beibu Gulf Basin

苏永进 唐跃刚 石胜群 房新娜

Su Yongjin Tang Yuegang Shi Shengqun Fang Xinna

在区域构造演化、构造单元划分及地层发育特征分析的基础上,对北部湾盆地迈陈凹陷东部地区,重点开展了储集层、油气成藏条件和主控因素研究,建立起研究区油气成藏模式。分析认为,古近系流沙港组、涠洲组是主要含油层系,包括4套储盖组合;主要烃源岩为流二段和流三段上部暗色泥岩,2套重要的砂岩储层是流三段和涠洲组;圈闭类型以断鼻、断块及地层超覆型为主,时间、空间上配置较好;成熟烃源岩、储层发育、断层特征、盖层条件和圈闭形态及落实程度是油气成藏的主控因素;研究区包括深凹带内斜坡带、南部断阶带和外斜坡、远斜坡带三种成藏模式,内斜坡带西部地区为勘探最有利的区带。

Based on the analysis of regional tectonic evolution,structural unit division and characteristics of strata development,the reservoirs,hydrocarbon pooling conditions and main controlling factors were studied to set up pool-forming models in the east of the Maichen Sag of the Beibu Gulf Basin.The Paleogene Liushagang and Weizhou formations (E and E respectively) are the dominant oil-bearing formations which include four sets of reservoir-seal combinations;the dark mudstone in the E and the upper E are the main source rocks;the E and Ew are two important sandstone reservoirs.The traps are mainly faulted nose,faulted block and stratigraphic overlap traps with good timing and spatial configurations.The predominant factors controlling pool-forming could be mature source rocks,reservoirs development,fault features,sealing conditions,configuration of traps and their workable degree.There are three hydrocarbon pooling models,including the inner-slope zone in the deep sag,fault bench in the south,outer-slope and far slope zone.The western part of inner slope zone is the most favorable area for further exploration.

10.11743/ogg20090212