珠江口盆地恩平凹陷西南部火山岩相和火山机构特征及其分布控制因素  

Characteristics and Controlling Factors of Distribution of Volcanic Facies and Volcanic Edifice in Southwestern Enping Sag, Pearl River Mouth Basin

作　　者：郝国丽[1] 蒋迪娅 许风光 张昊 金艳 刘洋 Hao Guoli;Jiang Diya;Xu Fengguang;Zhang Hao;Jin Yan;Liu Yang(College of Earth Sciences,Jilin University,Changchun 130061,China;Shenergy Oil and Gas(Shenzhen)Company Limited,Shanghai 200041,China)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]申能油气(深圳)有限公司,上海200041

出　　处：《吉林大学学报（地球科学版）》2024年第6期1951-1967,共17页Journal of Jilin University：Earth Science Edition

基　　金：申能油气(深圳)有限公司油气勘探项目(SZPC-KT-23-004);中国海洋石油有限公司“十四五”重大科技项目(KJGG-2022-0302)。

摘　　要：为了进一步掌握珠江口盆地恩平凹陷西南部火山岩发育模式和分布控制因素,本次研究基于珠江口盆地恩平凹陷火山岩研究区块及周边各项资料,首先通过薄片鉴定结合测井识别了火山岩岩性和岩相特征,然后采用井震结合研究了火山机构特征,再利用地球化学方法分析了火山岩成因。结果表明:恩平凹陷西南侧发育以玄武岩为主的火山岩,通过钻井资料,判别火山岩岩性4种,分别为玻质碎屑岩、块状玄武岩、杏仁体玄武岩和火山隐爆角砾岩;研究区新生代火山岩可划分为2相4亚相,分别为火山通道相隐爆角砾岩亚相,喷溢相板状熔岩流亚相、辫状熔岩流亚相和玻质碎屑岩亚相;依据沉积岩沉积界面识别4个喷发期次,并按期次划分了火山口—近火山口、近源、中源和远源4个相带;火山岩储层复杂,火山口—近火山口—近源相物性较好;不同期次玄武质岩浆由同源幔源岩浆经分离结晶作用形成,岩浆房位于下地壳,经历了强烈的地壳同化混染作用。对于分布控制因素,本次研究根据地震资料,识别了研究区两期活动断裂,珠江组沉积期呈NEE-NE向断裂,韩江组沉积期至今主要为NWW-NW向断裂;认为其岩浆来源与深部断裂有关,NW向的左旋走滑分量使火山机构相带走向向左有微弱旋转,且从带状逐渐过渡为反S形。In order to clarify the evolution model and controlling factors of distribution of volcanic rocks in the southwestern Enping sag,Pearl River Mouth basin,based on the datasets of the target area and adjacent area,the lithological and lithofacies characteristics are identified with thin section and logging firstly,then the volcanic edifice characteristics are identified with well and seismic datasets,finally,the genesis of volcanic rocks are identified with geochemical data.The results show that basalt-dominated volcanic rocks developed in southwestern Enping sag.Through drilling data,four types of volcanic rock are identified,namely hyaloclastite,massive basalt,amygdaloid basalt,and hydrothermal breccia.The Cenozoic volcanic rocks in the study area are divided into two kinds of lithofacies and four kinds of subfacies:Volcanic conduit facies(including hidden breccia subfacies),effusive facies(including hyaloclastic rock subfacies,tabular lava flow subfacies,and braid lava flow subfacies).At the same time,four eruption periods are identified based on sedimentary rock interfaces,and volcanic crater-near volcanic crater,proximal volcanic facies belts,middle-distance and distal volcanic facies belts are divided according to each period.Volcanic reservoirs are complex,and the physical properties of volcanic conduits-near volcanic crater and proximal volcanic facies belts are relatively good.The basaltic magma of different stages in the research area was formed by the separation and crystallization of homologous mantle derived magma.The magma chamber is located in the lower crust and has undergone strong crustal assimilation and mixing.According to the seismic data,it is identified that the fault in the study area is characterized by two phases of activity.The Pearl River Formation is NEE NE trending in the sedimentary period,and the Hanjiang Formation is NWW NW trending in the sedimentary period up to now.The origin of the magma is associated with deep-seated faults.The NW sinistral strike-slip component induces a weak

关 键 词：珠江口盆地 恩平凹陷 阳江—一统断裂带 火山岩相 火山机构 地球化学 储层 

分 类 号：TE122[石油与天然气工程—油气勘探]