Sedimentary characteristics and geological significance of a mixed-process delta for petroleum exploration in the Zhuhai formation of the Baiyun Depression,Pearl River Mouth Basin,China  

作　　者：Xiaojun Xie Wu Tang Shangfeng Zhang Rui Zhu Dongxu Fan Ran Li 

机构地区：[1]China National Offshore Oil Research Institute Limited,Beijing,100028,China [2]School of Geosciences,Yangtze University,Wuhan,Hubei,430000,China

出　　处：《Petroleum Research》2024年第4期599-609,共11页石油研究(英文)

基　　金：supported by the China National Offshore Oil Corporation(No.2021-KT-YXKY-05);the National Natural Science Foundation of China(No.41472098).

摘　　要：The Zhuhai Formation in the Baiyun Depression of the Pearl River Mouth Basin in the northern South China Sea is a marine delta influenced by multiple hydrodynamic forces,including rivers,waves,and tides,resulting in a mixed-process delta.As a result of the combined effects of these forces,the distri-bution patterns and reservoir structures in the sandstone formations of the Zhuhai Formation are extremely complex.This paper provides a detailed description of the coring section of the Zhuhai For-mation drilled in the Baiyun Depression,focusing on the lithology,sedimentary structure,special con-tainers,and depositional dynamics of the coring section.It also summarizes the characteristics of a hybrid power delta controlled by rivers,waves,and tides,and explores the geological significance of this mixed-process delta for oil and gas exploration.The study reveals that sedimentation controlled by rivers primarily consists of medium-to-fine sandstones with interbedded cross-bedding and parallel bedding.Scour-fill structures and a bell or box-shaped natural gamma ray logging curve(GR)are also observed.Seismic reflection exhibits strong amplitude and high continuity.Wave-controlled sedimentation,on the other hand,predominantly consists of silt and fine sandstones with scouring,wave-formed cross-bedding,abundant bioturbation,and a serrated and funnel-shaped GR curve.Seismic reflection shows medium amplitude and high continuity.Tidally-controlled deposits are characterized by thin interbeds of mudstone,siltstone,and fine sandstone,as well as vein laminations,undulating composite lamina-tions,lenticular laminations,and biclastic layers.The GR curves for tidally-controlled deposits are sharp or jagged with funnel shapes,and seismic reflections exhibit medium amplitude and continuity.The hydrodynamic features controlling sedimentation during the depositional period of the Zhuhai Forma-tion in the Baiyun Depression exhibit evident zonation on a planar scale,influenced by sedimentary paleogeography and sea-level changes.River con

关 键 词：Mixed-process delta Sedimentary characteristics Zhuhai formation Baiyun Depression Pearl River Mouth Basin 

分 类 号：P61[天文地球—矿床学]