陆丰13东洼文昌组碎屑锆石U-Pb年龄特征及其物源示踪意义  

Detrital zircon U-Pb age characteristics of Wenchang Formation in Lufeng 13 eastern sag and its significance for provenance tracing

作　　者：周凤娟 丁琳 马永坤 李晓艳 张月霞 赵梦 阙晓铭 ZHOU Fengjuan;DING Lin;MA Yongkun;LI Xiaoyan;ZHANG Yuexia;ZHAO Meng;QUE Xiaoming(CNOOC China Limited,Shenzhen Branch,Shenzhen,Guangdong 518054,China;CNOOC China Limited,Tianjin Branch,Tianjin 300459,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518054 [2]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《中国海上油气》2020年第4期46-55,共10页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司科技联合攻关项目“珠一坳陷不同构造带古近系有效储层发育机理及分布预测(编号:YXKY-2019-SZLH-01)”部分研究成果。

摘　　要：为示踪陆丰13东洼文昌组东北向长轴辫状河三角洲砂体物源,对研究区6口井11个砂岩岩屑样品进行了碎屑锆石U-Pb定年分析,结果表明以岩浆成因为主的锆石年龄谱具有多峰特征,主峰值年龄为156、430 Ma。结合源区基底残留地层的岩性特征、年龄特征,辅以薄片岩屑类型鉴定和重矿物物源示踪,分析认为文二段、文五段物源主要为中生代沉积岩,局部可能受到始新世喷出岩、中生代花岗岩物源的影响,而不是早期研究认为的文昌组物源以中生代花岗岩为主。这些认识解释了陆丰13东洼文昌组发育优质储层的根本原因,同时也为今后本区源-汇体系研究及优质储层预测提供了新的依据。To trace the provenances of sandbodies in the northeastern long-axis braided river delta of Wenchang Formation in Lufeng 13 eastern sag,11 sandstone cuttings samples from 6 wells in the study area are used to carry out a detrital zircon U-Pb dating analysis.The results show that the zircons are dominated by magmatogenic and the zircon age spectrum has multi-peak characteristics,with the main peak ages of 156 Ma and 430 Ma,respectively.Combined with the lithologic and age characteristics of basement residual strata in the source region,supplemented by thin section analysis of debris types and provenance tracing of heavy minerals,it is considered that the provenances of the second and fifth members of Wenchang Formation are mainly Mesozoic sedimentary rocks,which may be partially affected by the provenances of Cenozoic Eocene extrusive rocks and Mesozoic granites,rather than the previously considered Mesozoic granite provenance of Wenchang Formation.These understandings explain the fundamental reason for the development of high-quality Wenchang reservoirs in Lufeng 13 eastern sag,and provide a new basis for future study on source-sink systems and prediction of high-quality reservoirs in this region.

关 键 词：陆丰13东洼 文昌组 碎屑锆石U-PB年龄 物源示踪 优质储层 

分 类 号：TE121.3[石油与天然气工程—油气勘探]