宝岛凹陷北部陵水组古水系恢复及其源汇意义  

Restoration and source-sink significance of paleo-drainage of Lingshui Formation in northern Baodao Sag

作　　者：王雅宁[1,2] 李星露[1] 唐武 张尚锋 朱锐[1,2] WANG Yaning;LI Xinglu;TANG Wu;ZHANG Shangfeng;ZHU Rui(School of Geosciences,Yangtze University,Wuhan 430100,Hubei;Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education(Yangtze University),Wuhan 430100,Hubei;CNOOC Research Institute Co.Ltd.,Beijing 100028)

机构地区：[1]长江大学地球科学学院,湖北武汉430100 [2]油气资源与勘探技术教育部重点实验室(长江大学),湖北武汉430100 [3]中海油研究总院有限责任公司,北京100028

出　　处：《长江大学学报(自然科学版)》2025年第1期21-32,共12页Journal of Yangtze University(Natural Science Edition)

基　　金：中海石油(中国)有限公司科技专项“南海北部古近纪‘源-汇’体系及大中型储集体主控因素分析”(CCL2021RCPS0440RSN)。

摘　　要：海相断陷盆地断拗期演化复杂,构造活动强烈,“源-汇”格局复杂多变,关于盆缘砂体从物源区到汇聚区的搬运过程目前研究较为缺乏,并且对“源-汇”系统发育的制约因素探讨不够深入。以琼东南盆地宝岛凹陷北部渐新统陵水组为研究对象,以古水系精细刻画技术为核心,充分借助地化、测井、高精度三维地震等资料,阐明了宝岛凹陷物源基岩岩性、基岩年龄、重矿物组合特征、古沟道类型、水系组合、沉积体系分布规律等特征,重建了宝岛凹陷北部古水系空间展布特征,半定量刻画及分析了“源-渠-汇”系统要素之间的耦合联系。研究表明:宝岛凹陷物源主要来自海南岛(位于海南隆起区内)和神狐隆起,受断裂活动影响,盆缘地貌从西向东由断控转换为坡控;研究区共划分7个物源区,Ⅱ~Ⅳ、Ⅶ物源区主要发育古沟谷型古沟道,Ⅴ、Ⅵ物源区主要发育断槽型,呈现多水系共汇特征;宝岛凹陷陵水组早期共发育5套扇体,古沟道的类型、发育程度和规模、延伸展布则直接控制储集扇体的沉积类型、规模和展布特征,认为水系长度较短的U+W型宽缓古沟道+多分支水系+断阶控制下的扇体为有利储集体。The evolution of the fault depression period of the marine faulted basin is complex,the tectonic activity is strong,and the“source-sink”pattern is complex and changeable.At present,there is a lack of research on the transport process of the basin margin sand body from the source area to the convergence area,and the restriction factors of the development of the“source-sink”system are not discussed in depth.This paper takes Oligocene Lingshui Formation in the northern part of Baodao Sag in Qiongdongnan Basin as the research object,and uses the fine description technology of paleo-drainage system as the core.With the help of geochemical,drilling and high-precision three-dimensional seismic data,this paper expounds the characteristics of bedrock lithology,bedrock age,characteristics of heavy mineral assemblages,channel type,water system assemblage and sedimentary system distribution in Baodao Sag,reconstructs the spatial distribution characteristics of paleo-drainage system in the northern part of Baodao Sag,and semi-quantitatively describes and analyzes the coupling relationship between“source-channel-sink”system elements.The results show that Baodao Sag mainly comes from Hainan Island and Shenhu Uplift.Affected by the fault activity,the basin margin landform is transformed from fault control to slope control from west to east.The study area is divided into 7 source areas.Ⅱ~ⅣandⅦsource areas mainly develop paleo ravine-type channels,andⅤandⅥsource areas mainly develop fault-type paleo ravine types,showing the characteristics of multi-water system confluence.Five sets of fans were developed in early Lingshui Formation of Baodao Sag.The type,development degree and scale of paleo ravine and the extended distribution directly control the sedimentary type,scale and distribution characteristics of the reservoir fans.It is considered that the U+W type wide and gentle paleo ravine with short water system+multi-branch water system+fans under the control of fault terraces are favorable reservoirs.

关 键 词：古水系 宝岛凹陷 “源-汇”系统 渐新统陵水组 琼东南盆地 

分 类 号：P618.13[天文地球—矿床学] TE121.1[天文地球—地质学]