合水南地区长7段夹层型页岩油储层孔隙结构特征及主控因素  

Pore structure characteristics and main controlling factors of interbedded shale oil reservoirs of Chang 7 Member in South Heshui Area

作　　者：付林圃 王喜鑫 麻书玮 李少华[1] 薛婷 李强强 严睿 杨秦川 FU Linpu;WANG Xixin;MA Shuwei;LI Shaohua;XUE Ting;LI Qiangqiang;YAN Rui;YANG Qinchuan(Hubei Key Laboratory of Complex Shale Oil and Gas Geology and Development in Southern China,Yangtze University,Wuhan,Hubei 434100,China;Key Laboratory of Oil and Gas Resources Research in Gansu Province,Lanzhou,Gansu 730000,China;Exploration and Development Research Institute,PetroChina Changqing Oilfield Company,Xi'an,Shaanxi 710000,China)

机构地区：[1]长江大学南方复杂页岩油气地质与开发湖北省重点实验室,湖北武汉430100 [2]甘肃省油气资源研究重点实验室,甘肃兰州730000 [3]中国石油长庆油田分公司勘探开发研究院,陕西西安710000

出　　处：《东北石油大学学报》2025年第1期77-90,I0006,I0007,共16页Journal of Northeast Petroleum University

基　　金：中国石油科技创新基金项目(2021DQ02-0106);国家自然科学基金项目(42172172);甘肃省油气资源研究重点实验室开放基金项目(20221227)。

摘　　要：以鄂尔多斯盆地合水南地区长7段夹层型页岩油储层为例,利用铸体薄片、扫描电镜、XRD分析、高压压汞、恒速压汞及氮气吸附实验,分析合水南地区长7段夹层型页岩油储层孔隙结构特征,探讨沉积、成岩作用对孔隙结构的控制作用。结果表明:合水南地区长7段页岩油储层孔隙度平均为8.47%,渗透率平均为0.74×10^(-3)μm^(2),属于典型的超低孔、超低渗储层;孔隙类型以残余粒间孔和长石溶孔为主,孔喉半径集中分布在0.02~200.00μm之间,孔隙形态主要为板状平行狭缝孔和半封闭楔形孔;孔隙结构受沉积、成岩作用演化共同控制。沉积作用奠定页岩油储层的物质基础,沉积物粒度细,杂基体积分数高,原始孔渗低;储层在强压实阶段损失大量的粒间孔隙,胶结作用进一步降低储层物性;后期溶蚀作用的改造促使优势储层形成。砂质碎屑流砂体受胶结作用减孔大,浊流砂体受压实作用减孔大。砂质碎屑流砂体经历中等压实、强胶结及中等溶蚀,是研究区优势储层的主要成因。该结果对夹层型页岩油高效开发具有指导意义。In order to efficient development of interbedded shale oil.This study focuses on the Chang 7 Member of the Triassic Yanchang Formation in the South Heshui Area of the Ordos Basin.The pore structure characteristics of the Chang 7 interbedded shale oil reservoir were analyzed using cast thin sections,scanning electron microscopy(SEM),XRD analysis,high-pressure mercury injection,and low-temperature nitrogen adsorption.The impact of sedimentation and dominant diagenetic processes on pore structure was also examined.The results indicate that the interbedded shale oil reservoirs of the Triassic Chang 7 Member in South Heshui Area.With an average porosity of 8.47%and an average permeability of 0.74×10^(-3)μm^(2),it as a typical ultra-low porosity and ultra-low permeability reservoir.The reservoir pores are predominantly feldspar dissolution pores and residual intergranular pores.The pore throat radius range from 0.02 to 200.00μm,with pore throats primarily consisting of plate-like parallel slit pores and semi-closed wedge-shaped pores.Sedimentation,compaction,cementation,dissolution,and diagenetic sequences collectively control the pore structure.Sedimentation provides the material basis for the shale reservoir,characterized by fine grain size,high clay content,and low initial porosity and permeability.Strong compaction significantly reduces the number of intergranular pores,while cementation further degrades reservoir properties.However,subsequent dissolution partially enhances the reservoir’s porosity and permeability.The sandy debris flow reduction pore is greatly affected by cementation,and the turbid current reduction pore is greatly affected by compaction.The main causes of advantageous reservoirs are the sand debris flow undergose medium compaction,strong cementation,and medium dissolution in the research area.This result has guiding significance for the efficient development of interbedded shale oil.

关 键 词：陆相湖盆 夹层型页岩油 孔隙结构 砂质碎屑流 优势储层 长7段 合水南地区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]