Quantitative Analysis of Cenozoic Extension in the Qiongdongnan Basin, South China Sea: Insight on Tectonic Control for Hydrocarbon Reservoir Accumulation and Formation

Energies

卷:15

Lijun Mi¹  Yan Zhang²  Li Zhang²  Jie Zhou³  Jitian Zhu³  Xiaofeng Xiong³  Lishan Tang³  Xiangyang Lu⁴  Shiguo Wu⁴ 

[1] Beijing Institute of Research, China National Offshore Oil Corporation (CNOOC) Limited, Beijing 571000, China;

[2] Guangzhou Marine Geological Survey, National Engineering Research Center of Gas Hydrate Exploration and Development, Guangzhou 511458, China;

[3] Hainan Branch of China National Offshore Oil Corporation (CNOOC) Limited, Haikou 571000, China;

[4] Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China;

关键词: extension;    structure;    fractal;    hydrocarbon reservoir;    Qiongdongnan Basin;    South China Sea;   

DOI  :  10.3390/en15114011

来源: DOAJ

【 摘 要 】

Cenozoic extension rates were calculated based on 20 seismic profiles across the Qiongdongnan Basin, South China Sea. The results confirmed that the Cenozoic rifting in the Qiongdongnan Basin exhibited multistage extension and spatiotemporal variation. In terms of the N–S striking seismic profiles, the structural forms of the northern and southern sags of the basin were characterized by narrow half grabens, while the structure at the center sag of the basin was characterized by wide and gentle grabens. The fault strikes in the west of the basin were mainly northeast–southwest trending, whereas those in the east of the basin changed from northeast–southwest trending to nearly east–west trending. The extension rate in the east sag was higher than that in the west area. The extension rate in the middle part was lower relative to the east and west sags. This was because the rifting was controlled by the distribution of the main boundary fault along the basin. Temporally, the Cenozoic extension could be divided into three periods: Eocene, Oligocene, and Miocene. The amount of stretching in the three extension stages was unevenly distributed in the entire basin. The maximum was mainly in the Oligocene Lingshui and Yacheng Formations. The Oligocene extension occurred in the entire basin, and the Eocene extension was limited to the Ledong and Changchang sags. Significant fault activity could be observed during the deposition period of the Yacheng and Lingshui Formations and could be attributed to strong extensional activity. The rifting tectonics controlled the distribution of source rocks and oil-generating window as well as hydrocarbon generation, reservoir formation, and accumulation.

【 授权许可】

Unknown