地质科学2025，Vol.60Issue(4)：1164-1175,12.DOI:10.12017/dzkx.2025.076
吉木萨尔凹陷二叠系芦草沟组致密纹层特征与储层结构发育成因
Characteristics of tight laminations and genesis of reservoir structure in the Permian Lucaogou Formation of Jimsar Sag
摘要
Abstract
The tight reservoirs in the Lucaogou Formation of the Jimsar Sag are a key area for tight oil exploration and development in China.However,the complex laminar structure,strong reservoir heterogeneity,and unclear causes of reservoir structure development have restricted the exploration and development direction of the Lucaogou Formation in the Jimsar Sag.Through methods such as core observation,cast thin sections,scanning electron microscopy,two-dimensional large-area multi-scale combined electron microscopy imaging,and high-performance micro-area scanning,based on the analysis of reservoir rock type characteristics,the laminar structure and reservoir space differences in the upper and lower sweet-spot sections of the tight oil reservoir were studied,and the causes of reservoir structure development were discussed.The research shows that:1)the lithology of the Lucaogou Formation is very complex.The lithologies in the sweet-spot sections are mainly six types,including dolomitic siltstone,silty dolomite,feldspar lithic sandstone,sandy dolomite,dolomitic mudstone,and argillaceous siltstone.2)The laminar structure of the Lucaogou Formation is relatively well developed.It mainly develops interbedded silt-mud laminations,mud laminations,interbedded micritic dolomite-mud laminations,a small number of algal laminations,and tuffaceous laminations.The laminar reservoir rocks in the study area have the best oil-bearing property,followed by the layered ones,and the massive ones are the worst.3)The total porosity of the Lucaogou Formation ranges from 2.19％to 3.99％.Among them,the porosity of inorganic pores and inorganic fractures ranges from 1.9％to 3.68％,and the pores are mainly of inorganic origin.The pore types are mainly secondary pores,and primary pores are basically undeveloped.Only a small amount of remaining primary pores is preserved in some reservoirs with relatively good physical properties in the sweet-spot sections.4)The formation of the laminar structure is mainly due to the increase in clay content.During bottom-current transportation,silt and clay are sorted,and silt and clay laminations are superimposed.The development of carbonate laminations is mainly related to algal growth and lake water chemical deposition,while massive reservoir rocks are formed under strong hydrodynamic conditions.It is concluded that the laminar and layered reservoirs have high organic matter content and good oil-bearing property due to their slow subsidence rate,and they are the sweet-spot exploration targets in the study area.The research results provide a theoretical basis for further exploration and research of high-quality sweet-spot sections in the Lucaogou Formation,and also provide theoretical support for the study of tight oil sweet-spot reservoir characteristics.关键词
吉木萨尔凹陷/芦草沟组/页岩油/甜点储层/纹层结构/储层结构Key words
Jimsar Sag/The Lucaogou Formation/Shale oil/Sweet spot reservoir/Laminar structure/Reservoir structure分类
天文与地球科学引用本文复制引用
韩宝,陈晓轩,何周,赵俊,王燕娥,马智斌,宋嘉楠,赵晓东..吉木萨尔凹陷二叠系芦草沟组致密纹层特征与储层结构发育成因[J].地质科学,2025,60(4):1164-1175,12.基金项目
新疆维吾尔自治区"一事一议"引进战略人才项目(编号:XQZX20240054)和新疆维吾尔自治区重点研发专项"盆地超深层复杂断裂带油气成藏评价技术开发"(编号:2024B01015-3)资助 （编号:XQZX20240054）
