海相油气地质2025，Vol.30Issue(1)：30-40,11.DOI:10.3969/j.issn.1672-9854.2025.01.003
琼东南盆地断阶带地貌控制下的辫状河三角洲发育特征
Development characteristics of braided river delta under geomorphic control of fault step zone in Qiongdongnan Basin:taking the 3rd member of Oligocene Lingshui Formation in the northern slope of Baodao Sag as an example
摘要
Abstract
Qiongdongnan Basin,a passive continental deep-water basin in the north of the South China Sea,is an important natural gas base in China.The deep Oligocene Lingshui Formation in Qiongdongnan Basin represent a primary target for forthcoming exploration in the South China Sea,however,due to limited exploration efforts,the sedimentary system of the Lingshui Formation remains inadequately characterized.Based on core,logging and 3D seismic data,the sedimentary characteristics of Lingshui Formation in northern slope of Baodao Sag,Qiongdongnan Basin are systematically dissected.It is clear that Lingshui Formation can be subdivided into two third-order sequences.The sedimentation of the 3rd member of Lingshui Formation is a complete three-order sequence with low,transgressive and high system domains.Under the control of the fault co directional transition zone and transition slope formed by the differential activity of F12 fault,several large differentiated river delta groups of different scales in the west and east are developed in the 3rd member of Lingshui Formation.The fault step zone mainly developed the underwater distributary channel of braided river delta front in the late low and high system tracts,and it is a high-quality reservoir development interval with the thickness of sand body being large,the particle size being coarser,the separation being better,and the physical property being better.Therefore,the development model of multistage fault-controlled material source and transition fault-controlled sand body distribution of the 3rd member of Lingshui Formation in the northern fault step zone of Baodao Sag is established.The high quality reservoir of large-scale delta distributary channel of the 3rd member of Lingshui Formation directly covers the source rock of Yacheng Formation and forms a favorable transport system with source rock-linked fault.And it is covered by thick transgressive shallow-sea mudstone deposited in late depression period.High-quality reservoer-cap combination and transport system are the key to forming large gas fields in Baodao Sag,and are worth of more attention in the future exploration.关键词
辫状河三角洲/断阶带/陵水组三段/古近系/宝岛凹陷/琼东南盆地Key words
braided river delta/fault step zone/the 3rd member of Lingshui Formation/Paleogene/Baodao Sag/Qiong-dongnan Basin分类
石油、天然气工程引用本文复制引用
邓孝亮,汪紫菱,尤丽,詹冶萍,周晨..琼东南盆地断阶带地貌控制下的辫状河三角洲发育特征[J].海相油气地质,2025,30(1):30-40,11.基金项目
本文受中海石油(中国)有限公司科技项目"南海大中型天然气田形成条件、勘探潜力与突破方向"(编号:KJZH-2021-0003-00)、中国海洋石油集团有限公司"十四五"重大科技项目"南海北部深水区勘探关键技术"(编号:KJGG2021-0100)和海南省"南海新星"科技创新人才平台项目"宝岛凹陷东南缘超深水天然气优质储层识别及成藏机理研究"(编号:NHXXRCXM202367)联合资助 （中国）
