南海北部陆缘渐进式裂陷控制烃源岩差异分布  

Progressive rifting controls the differential distribution of source rocks in the northern continental margin of the South China Sea

作　　者：张功成 封从军[1,2] 陈莹[3] 曾清波 杨东升 郭帅 焦保程 姚兴宗 葛艳龙 ZHANG Gongcheng;FENG Congjun;CHEN Ying;ZENG Qingbo;YANG Dongsheng;GUO Shuai;JIAO Baocheng;YAO Xingzong;GE Yanlong(State Key Laboratory of Continental Dynamics,Northwest University,Xi’an,Shaanxi 710069,China;Department of Geology,Northwest University,Xi’an,Shaanxi 710069,China;CNOOC Research Institute Ltd.,Beijing 100028,China)

机构地区：[1]西北大学大陆动力学国家重点实验室,陕西西安710069 [2]西北大学地质学系,陕西西安710069 [3]中海油研究总院有限责任公司,北京100028

出　　处：《中国海上油气》2025年第2期27-44,共18页China Offshore Oil and Gas

基　　金：国家自然科学基金企业创新发展联合基金重点支持项目“南海北部深水区深层温压场差异性演化对优质储层的控制机理(编号:U24B2016)”;国家自然科学基金项目“南海深海地质演变对油气资源的控制作用(编号:91528303)”部分研究成果;国家重点基础研究发展计划(973)项目“南海深水盆地油气资源形成与分布基础性研究(编号:2009CB219400)”。

摘　　要：南海北部陆缘深水区是中国海域油气勘探重要的地区之一。然而对该区相邻盆地成盆机制、湖相及煤型烃源岩有利区分布及油气成藏机制等方面认识不清。以年代地层与生物地层格架建立为基础,对南海北部深水区古近系地层展布和结构进行了对比分析,揭示了差异成盆机制和烃源岩发育机制,进一步探讨了南海北部油气成藏模式。研究表明:(1)南海北部陆缘深水区古近纪构造演化具东早西晚渐进式裂陷特征,珠江口盆地早中始新世处于区域断陷、晚始新—早渐新世主体处于断拗、晚渐新世处于拗陷阶段,琼东南盆地始新世处于初始断陷、早渐新世处于断陷、晚渐新世处于断拗演化阶段。(2)珠江口盆地深水区湖相烃源岩发育于早中始新世,强断深凹为半深湖—深湖烃源岩提供了有利的发育条件。同时,受断-拆作用控制宽缓斜坡带发育规模外浅湖相烃源岩;琼东南盆地深水区湖相烃源岩发育晚于珠江口盆地,零星发育岭头组断陷湖盆。(3)珠江口盆地深水区煤型烃源岩主要发育于晚始新世,主要分布于凹陷中部和白云东洼的洼槽区;琼东南盆地深水区煤型烃源岩主要发育于早渐新世,形成3个中小规模煤系(扇)三角洲带。(4)珠江口盆地深水区湖相烃源灶凹陷内,原油成藏过程中深入烃源岩内的输导砂体具有“泵吸”效应,凹陷内断层的“脆韧二元性”特征控制了原油垂向运移顶板层位;琼东南盆地深水区煤型烃源岩发育区内,超压和优势断面汇聚脊构成“砂-断”接力天然气近源高效成藏模式。研究成果为南海北部深水区的不同类型与分布下的烃源岩贡献的油气类型提供勘探理论指导。The deep-water area of the northern continental margin of the South China Sea is a key region for oil and gas exploration in China’s maritime territory.However,there are still uncertainties regarding the basin-forming mechanisms,the favorable area distribution of lacustrine and coal-measure source rocks,and the oil and gas accumulation processes in adjacent basins in the area.Hence,this study established a chronostratigraphic and biostratigraphic framework to conduct a comparative analysis of the Paleogene strata distribution and structure in the deep-water area of the northern South China Sea,revealed differential basin-forming mechanisms and source rock development patterns,and further elucidated the oil and gas accumulation models in the northern South China Sea.The research reveals the following:①The Paleogene tectonic evolution in the deep-water area of the northern continental margin of the South China Sea shows a progressive rifting pattern with earlier activity in the east and later in the west.The Pearl River Mouth Basin underwent various tectonic stages:fault in the early-middle Eocene,fault-depression in the late Eocene and early Oligocene,and depression in the late Oligocene.The Qiongdongnan Basin followed the pattern of initial fault in the Eocene,fault in the early Oligocene,and fault-depression in the late Oligocene.②Lacustrine source rocks developed in the early-middle Eocene in the deep-water area of the Pearl River Mouth Basin.Intense faulting favored the development of semi-deep lake and deep lacustrine source rocks.Shallow lacustrine source rocks developed in wide and gentle slope belts beyond the scale,which was controlled by faulting and detachment.Lacustrine source rocks developed in the deep-water area of Qiongdongnan Basin later than those in Pearl River Mouth Basin,with fault lake basins of the Lingtou Formation developing sporadically.③Coal-measure source rocks mainly formed in the late Eocene in the deep-water area of the Pearl River Mouth Basin,mainly distributed in the sag ce

关 键 词：深水区 南海北部 渐进式裂陷 湖相烃源岩 煤型烃源岩 油气分布 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P744.4[天文地球—海洋科学]