渤中19-6气田变质岩储层热液型裂缝充填物及油气地质意义  

Metamorphic Buried Hill Reservoir of Bozhong 19–6 Gas Field:The Characteristics of Hydrothermal Fracture Fillings and Their Geological Significance of Petroleum

作　　者：周翊 郭玉洁 罗宇航 王岩松 唐洪明[1] ZHOU Yi;GUO Yujie;LUO Yuhang;WANG Yansong;TANG Hongming(School of Geoscience and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500

出　　处：《西南石油大学学报（自然科学版）》2024年第5期80-96,共17页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家自然科学基金(42302114);四川省自然科学基金(2022NSFSC0256);国家级大学生创新创业训练计划(20210615060)。

摘　　要：渤海湾盆地渤中19-6气田是2018年勘探发现的特大型凝析气田。变质岩潜山储集系统中发育的裂缝是油气的主要渗流通道和储集空间,而裂缝充填物记录了储集层的流体作用及演化过程,故针对裂缝充填物的系统研究对于油气勘探开发具有重要意义。在系统观察渤中19-6气田典型岩芯铸体薄片的基础上,综合运用电子探针、LA-ICPMS、阴极发光和荧光分析等实验方法,分析裂缝充填物的地球化学特征及其与烃类物质的赋存关系,探讨研究区储层经历的热液活动和油气运移特点及热液活动对变质岩储层物性的影响。研究表明:1)热液型裂缝充填矿物主要由镁菱铁矿+铁白云石+石英、镁菱铁矿+石英、铁白云石+石英3种矿物组合构成;2)镁菱铁矿和铁白云石的原位微区地球化学特征显示其为同期热液流体成因;3)烃类物质主要为赋存于铁白云石中的束缚沥青和赋存于镁菱铁矿中的烃类包裹体,热液活动和油气运移具有同时性,属于同期发生的两类地质事件;4)热液流体对于储集岩裂缝的闭合作用远大于溶蚀扩张作用,对储集岩物性主要起破坏作用。The Bozhong 19–6 Gas Field within metamorphic buried hills is a giant one discovered in 2018.The fractures developed in the metamorphic rock buried hill reservoir system are the main seepage channels and storage spaces for oil and gas,and the fracture fillings record the fluid action and evolution process of the reservoir.Therefore,systematic research on fracture fillings is of great significance for oil and gas exploration and development.Based on systematic observation of cores and the casting thin sections from metamorphic buried hill reservoir,we illustrate the geochemical characteristics of the hydrothermal fluid activity and petroleum migration happening to the reservoir and the hydrothermal influence on the reservoir using electron microprobe analysis,LA-ICPMS,cathodoluminescence and fluorometric analysis.The results show that:1)hydrothermal minerals in fractures include three types of aessemblages which are magnesian siderite+ankerite+quartz,magnesian siderite+quartz,ankerite+quartz.2)the in-situ geochemical characteristics of magnesian siderite and ankerite indicate the genesis of contemporaneous hydrothermal fluids.3)hydrocarbons are usually occurred as fixed bitumen hosted in ankerite and inclusions hosted in magnesian siderite.The hydrothermal activity and petroleum migration likely took place at the same time and they were the two contemporaneous geological events.4)more than the corrosion effect that the hydrothermal fluid took,hydrothermal fluid closing the fractures had damaged the physical property of the reservoir.

关 键 词：渤海湾盆地 渤中19-6气田 变质岩潜山 裂缝充填物 热液矿物 

分 类 号：TE122[石油与天然气工程—油气勘探] P595[天文地球—地球化学]