唐旭,张向涛,余一欣,等. 珠江口盆地陆丰凹陷南部古近系断裂发育特征与油气成藏[J]. 海洋地质与第四纪地质,2023,43(3): 132-143. doi: 10.16562/j.cnki.0256-1492.2022071201
引用本文: 唐旭,张向涛,余一欣,等. 珠江口盆地陆丰凹陷南部古近系断裂发育特征与油气成藏[J]. 海洋地质与第四纪地质,2023,43(3): 132-143. doi: 10.16562/j.cnki.0256-1492.2022071201
TANG Xu,ZHANG Xiangtao,YU Yixin,et al. Fault characteristics and hydrocarbon accumulation in the southern Lufeng Sag, Pearl River Mouth Basin[J]. Marine Geology & Quaternary Geology,2023,43(3):132-143. doi: 10.16562/j.cnki.0256-1492.2022071201
Citation: TANG Xu,ZHANG Xiangtao,YU Yixin,et al. Fault characteristics and hydrocarbon accumulation in the southern Lufeng Sag, Pearl River Mouth Basin[J]. Marine Geology & Quaternary Geology,2023,43(3):132-143. doi: 10.16562/j.cnki.0256-1492.2022071201

珠江口盆地陆丰凹陷南部古近系断裂发育特征与油气成藏

Fault characteristics and hydrocarbon accumulation in the southern Lufeng Sag, Pearl River Mouth Basin

  • 摘要: 陆丰凹陷是位于珠江口盆地珠I坳陷内的富烃凹陷,凹陷南部地区古近系具有良好勘探潜力。以三维地震资料解释成果和钻井资料为基础,分析陆丰凹陷南部地区断裂发育特征及演化过程,明确断裂对油气运聚成藏的控制作用,划分油气成藏组合类型。陆丰凹陷南部发育3个半地堑结构的洼陷,分别受活动性较强的3条铲式边界断裂控制。断裂主要发育于古近纪,斜坡带部位发育密度大,平面优势走向由深层NEE向至浅层近S-N向偏转,断裂密集带自东向西迁移。断裂可分为三级,分别控制洼陷结构、局部构造带和构造圈闭的形成。依据活动期次可划分出文昌期活动断层、恩平期活动断层和文昌-恩平期活动断层。陆丰凹陷南部地区断裂控制着断鼻、断块及断背斜圈闭的形成,断裂与烃源岩的组合类型差异影响着油气运聚效率。综合油气富集层系、输导方式、断裂活动性及源-断组合类型等成藏要素,建立源内自生自储型、源内自生上储型、源外旁生侧储型和源外下生上储型等4类油气成藏组合类型,对下一步油气勘探实践具有理论指导意义。

     

    Abstract: The Lufeng Sag is a hydrocarbon-rich sag located in Zhu I depression of the Pearl River Mouth Basin, and the Paleocene in the southern sag has good exploration potential. Based on the 3D seismic data interpretation and drilling data, we analyzed the characteristics of fault deformation and evolution in the southern Lufeng Sag, and the controls of faults on hydrocarbon transport and accumulation. In addition, the types of hydrocarbon combinations were classified. Three half-grabens in the southern Lufeng Sag were controlled by three listric boundary faults with strong activity. The faults were mainly developed during the Paleogene. The distribution density of faults is the highest in the slope zones, and the dominant trends changes from NEE to nearly SN upwards. Also, the dense zone of faults migrates from east to west. The faults can be divided into hierarchical classes 1 to 3, Class 1 the formation of sags, Class 2 determines local structural belts, and Class 3 restrains structural traps. The faults in the southern Lufeng Sag were active during the deposition periods of the Wenchang Formation, the Enping Formation, and the Wenchang-Enping Formations. The faults control the formation of fault noses, fault blocks, and fault anticlinal traps, and the difference in combination models of faults and source rocks affects the efficiency of hydrocarbon migration and accumulation. Based on the hydrocarbon accumulation factors such as enrichment strata, transportation models, fault activity, and source-faults combination types, four hydrocarbon accumulation models were established: in-source autogenous self-storage, in-source autogenous up-storage, out-source side-storage and out-source down-storage This study provided a theoretical support for further oil and gas exploration in the southern Lufeng Sag.

     

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