水下就位熔岩流相结构模式和储层意义:以义县地区白垩系义县组为例  

Facies architecture and reservoir significances of subaqueous lava flow:a case study of Cretaceous Yixian Formation in Yixian area

作　　者：张莹 刘志峰 朱文奇 王剑 卞海越 张津铭 唐华风[2] ZHANG Ying;LIU Zhifeng;ZHU Wenqi;WANG Jian;BIAN Haiyue;ZHANG Jinming;TANG Huafeng(CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;College of Earth Sciences,Jilin University,Changchun 130061,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]吉林大学地球科学学院,长春130061

出　　处：《世界地质》2024年第2期255-262,共8页World Geology

基　　金：国家重点研发计划课题(2022YFF0800403);中国海洋石油集团有限公司重大课题(KJGG2022-0301)。

摘　　要：水下就位熔岩流是盆地充填的重要类型,但相结构模式、储层分布规律和潜力特征还不清晰。为了阐明这些关键要素,本研究选取义县地区出露的义县组水下就位熔岩流作为研究对象,利用地质调查、岩矿鉴定和图像分析等方法开展岩石类型、岩相和储层特征研究。结果表明:①水下就位熔岩流岩性主要由熔岩和玻质碎屑岩组成,为喷溢相水上喷发水下就位熔岩流亚相,具体包括复合熔岩流和原地碎屑堆积两种微相,微相叠置关系呈现以复合熔岩流微相为主体、以原地碎屑堆积微相为主体和两种微相比例相当三种;②垂向上相序有原地碎屑堆积微相--复合熔岩流微相和只有原地碎屑堆积微相两种,横向上相序为复合熔岩流微相--原地碎屑堆积微相;③在研究区共识别出4类8型孔隙,复合熔岩流微相储层以气孔和淬火缝为主,原地碎屑堆积微相储层以次生溶蚀孔为主,面孔率分析结果显示原地碎屑堆积微相的储层好于复合熔岩流微相的储层,推测水下熔岩流前缘部分可能好于其根部。Subaqueous emplacement lava flow is an important type of basin filling,and its facies architecture,reservoir distribution patterns and potential characteristics are still unclear.In this paper,the subaqueous emplacement lava flow of Yixian Formation in Yixian area is taken as an example to study the rock types,lithofacies and reservoir characteristics by using the methods of geological survey,rock and mineral identification and image analysis.The results show as follows:①the lithology of the subaqueous lava flow includes lava and hyaloclastite,which can be divided into two kinds of microfacies:composite lava flow microfacies(CLFM)and in situ deposition of clastic microfacies(SDCM)of subaerial erpuptive-subaqueous emplacement lava flow subfacies in effusive facies.There are three overlapping type of CLFM and SDCM,namely dominated by CLFM,dominated by SDCM,and the equal proportion of CLFM and SDCM.②the vertical facies sequence is SDCM to CLFM or only SDCM.The lateral facies sequence is CLFM to SDCM.③4 types and 8 subtypes of porosities were identified.The pore of CLFM is dominated by vesicles and quenched fractures,and the pore of SDCM is dominated by secondary dissolution pore.The value of surface porosity of SDCM is higher than that of CLFM.It is inferred that the reservoir in the front part of the subaqueous lava flow should be better than that in root part.

关 键 词：水下熔岩流 火山岩相 义县组 白垩系 义县地区 

分 类 号：P618.13[天文地球—矿床学]