南羌塘坳陷中侏罗统布曲组含油白云岩储层特征  

CHARACTERISTICS OF OIL-BEARING DOLOMITE RESERVOIR IN MIDDLE JURASSIC BUQU FORMATION,SOUTH QIANGTANG DEPRESSION

作　　者：谢渝 史建南[1,2] 文华国 付小东[3] 宋春彦[2] 王家钦 韩灏 XIE Yu;SHI Jiannan;WEN Huaguo;FU Xiaodong;SONG Chunyan;WANG Jiaqing;HAN Hao(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Key Laboratory of Sedimentary Basin and Oil and Gas Resources,Ministry of Natural Resources,Chengdu,Sichuan610218,China;PetroChina Hangzhou Institute of Geology,Hangzhou,Zhejiang 310023,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]自然资源部沉积盆地与油气资源重点实验室,四川成都610218 [3]中国石油天然气股份有限公司杭州地质研究院,浙江杭州310023

出　　处：《矿物岩石》2024年第2期194-203,共10页Mineralogy and Petrology

基　　金：国家自然科学基金面上项目(批准号:41172120);自然资源部沉积盆地与油气资源重点实验室基金项目(编号:cdcgs2022001);中国石油“十四五”前瞻性基础性重大科技项目(编号:2021DJ0802)。

摘　　要：针对南羌塘坳陷中侏罗统布曲组白云岩含油信息丰富,该层位的储集特征不够清晰现状,本次研究利用露头及岩心样品从染色薄片、铸体薄片、孔渗测试及包裹体显微荧光、均一温度等多方面展开了岩石学特征、孔渗特征、流体包裹体及成岩作用的研究。研究结果表明:1)南羌塘坳陷中侏罗统布曲组至少发育5类白云岩,即粉晶、细晶、中晶、粗晶以及不等晶白云岩;2)孔隙和裂缝极为发育,其孔渗特征表明南羌塘坳陷布曲组中侏罗含油白云岩为中孔中渗储层;3)含油白云岩中的油气包裹体主要发育有2期,分布于白云岩、方解石内和晚期充填方解石脉内,早期主要分布于粉、细晶白云岩中,成熟度中等,荧光呈蓝绿色,同期含烃盐水包裹体均一温度为45~75℃;晚期要分布于中、粗晶白云岩中,成熟度较高,荧光呈蓝色,同期含烃盐水包裹体均一温度为105~120℃,有部分温度异常高,推测充注过程可能受一定热事件的影响;4)成岩作用显著,主要以压实、压溶、破裂、溶蚀以及交代作用为主,成岩作用与油气充注关系:细、粉晶白云石-油气充注-孔隙边缘鞍状白云石/白云石加大边-油气充注缝洞充填方解石-残余沥青。南羌塘坳陷中侏罗统布曲组储层特征综合研究,为该地区下一步的油气勘探具有一定的指导意义及实用价值。Based on the dolomite outcrop and core samples from the Middle Jurassic Buqu Formation in the South Qiangtang Depression,this study investigates petrology,porosity,permeability characteristics,fluid inclusions,and diagenesis to elucidate unclear reservoir characteristics.The key findings are as fol-lows:1)Dolomite Types:The Buqu Formation exhibits at least five types of dolomites,including pow-dery,fine,medium,coarse,and unequal crystalline dolomites.2)Porosity and Permeability:Well-devel-oped pores and fractures characterize the formation,indicating it as a medium porosity and medium perme-ability reservoir.3)Fluid Inclusions:Oil and gas inclusions primarily occur in two stages,distributed within dolomites,calcite,and late-filled calcite veins.During the early stage,oil and gas inclusions are mainly found in powdery and fine crystalline dolomites with medium maturity and blue-green fluorescence.Homogenization temperatures range from 45 to 75℃.In the late stage,these inclusions are present in medium and coarse crystalline dolomites with high maturity and blue fluorescence,with homogenization temperatures of 105 to 120℃.Some inclusions exhibit abnormally high temperatures,suggesting poten-tial thermal event influence during the charging process.4)Diagenesis:Significant diagenesis processes in-clude compaction,pressure dissolution,fracture,dissolution,and metasomatism.The relationship be-tween diagenesis and oil and gas charging involves fine and powdery dolomite,followed by oil and gas fill-ing,saddle-shaped dolomite formation or dolomite enlargement at pore edges,and subsequent oil and gas filling,fissure filling,calcite filling,and residual asphalt formation.This comprehensive study on the res-ervoir characteristics of the Middle Jurassic Buqu Formation in the South Qiangtang Depression holds guid-ing significance and practical value for future oil and gas exploration efforts in the area.

关 键 词：含油白云岩 储层特征 流体包裹体 布曲组 南羌塘坳陷 

分 类 号：P618.13[天文地球—矿床学]