珠江口盆地惠西南地区新近系岩性圈闭形成条件及发育类型  

Formation conditions and development types of Neogene lithologic traps in southwestern Huizhou area,Pearl River Mouth Basin

作　　者：朱明 陈维涛 杜家元 颜承志 刘汉卿 ZHU Ming;CHEN Weitao;DU Jiayuan;YAN Chengzhi;LIU Hanqing(Shenzhen Branch,CNOOC,Shenzhen City,Guangdong Province,518000,China;CAS Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou City,Guangdong Province,510301,China;University of Chinese Academy of Sciences,Beijing City,100049,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518000 [2]中国科学院南海海洋研究所中国科学院边缘海与大洋地质重点实验室,广东广州510301 [3]中国科学院大学,北京100049

出　　处：《油气地质与采收率》2019年第6期62-69,共8页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项“南海东部海域勘探新领域及关键技术”（2016ZX05024-004）

摘　　要：珠江口盆地惠西南地区是南海北部陆架区岩性圈闭勘探的首选靶区,已发现岩性油气藏石油地质储量近亿方,对该区岩性圈闭的形成条件、发育类型进行分析有利于明确岩性圈闭勘探方向,提升陆架区海相沉积体系岩性圈闭的勘探潜力。受多期相对海平面变化和复杂水动力条件影响,新近纪古珠江三角洲沉积形成的多成因砂体具有分带性发育和多层系储盖组合纵向叠置的特点,这为岩性圈闭的发育创造了物质基础;东沙运动使东沙隆起在新近纪晚期抬升,断裂体系发育,这为岩性圈闭形成提供了构造背景。惠西南地区岩性圈闭分为三角洲平原带、三角洲前缘带和条带砂发育带3个区带。三角洲平原带以河道型岩性圈闭为主;三角洲前缘带以岩性上倾尖灭圈闭为主,可进一步细分为前积末端砂体岩性上倾尖灭圈闭、前积内幕砂体岩性上倾尖灭圈闭和退积砂体岩性上倾尖灭圈闭;条带砂发育带以形成于局限古地貌背景下的条带状砂岩圈闭为主。分析不同类型圈闭的发育位置、尖灭特征及储层物性,认为退积砂体岩性上倾尖灭圈闭具有最好的储集物性和圈闭边界条件。The southwest Huizhou area in Pearl River Mouth Basin is the preferred target for lithologic trap exploration in the northeastern continental shelf of South China Sea. Nearly100 million square meters of petroleum geological reserves have been found in lithologic reservoirs. The analysis of forming conditions for lithologic traps and its developing types is beneficial to clarify exploration direction and enhance exploration potential of lithologic trap in marine sedimentary of the continental shelf. Influenced by multi-stage origin,relative sea-level change and complex hydrodynamic environment,multi-genesis sand bodies formed at Neogene paleo-Pearl River Delta are characterized by zonal development and vertical overlapping of multi-layer reservoir-cap assemblages,which are the material basis for lithologic traps development. Dongsha Movement makes Dongsha Uplift rise upper at the late Neogene and faults relatively develop,which provides tectonic background for lithologic traps formation. The lithologic traps in the southwestern Huizhou area distribute in three belts which are delta plain,delta front,and belt sand development zone. The channel sand bodies mainly develop in delta plain.The lithologic updip pinchout traps mainly develop at delta front,which can be further subdivided into three categories:the end sand body of progradation,the inner sand body of progradation,and the sand body of retrogradation. The strip sandstone traps develop mainly in strip sandstone development belts formed under the limited paleogeomorphic background.Based on the analysis of the development location,pinchout characteristics and reservoir physical properties of different types of traps,it is concluded that the lithologic updip pinchout traps of the sand bodies of retrogradation have the best reservoir physical properties and trap boundary conditions.

关 键 词：岩性圈闭 砂体成因 岩性尖灭 古珠江三角洲 惠西南地区 珠江口盆地 

分 类 号：TE112.31[石油与天然气工程—油气勘探]