致密砂岩储层孔隙结构特征对可动流体赋存的影响:以鄂尔多斯盆地庆城地区长7段为例  

Pore throat structure characteristics of tight sandstone reservoirs and their influence on movable fluid occurrence:Taking the Chang-7 Member of Qingcheng area of Ordos Basin as an example

作　　者：石桓山 胡望水[1,2] 李涛[1,2] 李亦博[4] 卢丹阳 刘国文 SHI Huanshan;HU Wangshui;LI Tao;LI Yibo;LU Danyang;LIU Guowen(College of Earth Science,Ministry of Education,Yan-gtze University,Wuhan 430199,China;Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Yan-gtze University,Wuhan 430199,China;Henan Oilfield Petroleum Engineering Technology Research Institute,SINOPEC,Nanyang Henan 473000,China;Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]长江大学地球科学学院,武汉430199 [2]长江大学油气资源与勘探技术教育部重点实验室,武汉430199 [3]中国石化河南油田石油工程技术研究院,河南南阳473000 [4]郑州大学,郑州450001

出　　处：《地质科技通报》2024年第2期62-74,共13页Bulletin of Geological Science and Technology

摘　　要：分析孔隙结构和可动流体分布特征是储层研究的关键要素,也是当前研究的重点与热点,对致密砂岩油气勘探及提高油气采收率具有重要意义。以鄂尔多斯盆地庆城地区长7段致密砂岩储层为例,通过物性测试、铸体薄片、扫描电镜、高压压汞和核磁共振实验,结合分形理论,分析了致密砂岩储层孔隙结构、非均质性和可动流体分布特征,讨论了孔喉结构和非均质性对可动流体赋存的影响。结果表明:研究区长7段储层储集空间主要由微纳米级孔隙贡献,孔隙连通性较差,孔喉半径主要分布在0.050~0.500μm;孔喉结构非均质性较强,分形维数分布在2.65~2.90;流体可动性较差,可动流体饱和度分布在16.68%~51.74%,可动流体多分布在中孔和小孔内。研究区长7段储层可分为3类:从Ⅰ类到Ⅲ类储层,剩余粒间孔和粒间溶蚀孔发育变少,孔隙连通性变差,孔喉尺寸变小,较大孔喉变少,非均质性变强,流体可动性变差,中孔和大孔内可动流体含量趋于降低,可动流体倾向于在小孔内赋存。研究成果为致密砂岩油气勘探及油气采收率提高提供了理论依据。[Objective] The analysis of pore structure and movable fluid distribution characteristics is the key element of reservoir research and is also the focus and hotspot of current research.It is of great significance for exploring tight sandstone oil and gas and improving oil and gas recovery.[Methods] The Chang-7 Member tight sandstone reservoir in the Qingcheng area of Ordos Basin was selected as the research object in this paper.Combined with fractal theory,through physical property tests,casting thin section,scanning electron microscopy(SEM),high-pressure mercury injection,and nuclear magnetic resonance(NMR) experiments,the pore throat structure,heterogeneity,and movable fluid distribution characteristics of tight sandstone reservoirs were analysed,and the influence of the pore throat structure and heterogeneity on movable fluid occurrence was discussed.[Results] The results show that the reservoir space of the Chang-7 Member reservoir in the study area is mainly contributed by micro-nanopores,which have poor pore connectivity.The pore throat radius is mainly 0.050-0.500 μm.The heterogeneity of the pore throat structure is strong,and the fractal dimension distribution is between 2.65 and 2.90.The fluid mobility is poor,and the movable fluid saturation is distributed between 16.68 % and 51.74 %,the movable fluid is mostly distributed in medium and small pores.The Chang-7 Member reservoirs in the study area can be divided into three types.From the type Ⅰ reservoir to the type Ⅲ reservoir,the development of residual intergranular pores and intergranular dissolution pores decreases,and the pore connectivity becomes poorer,and the pore throat size decreases,and the content of larger pore throats decreases,and the heterogeneity becomes stronger,and the fluid mobility is worse,and the movable fluid content in the medium and large pores tends to decrease,and movable fluid tends to occur in the small pores.[Conclusion] This study provides a theoretical basis for tight sandstone oil and gas exploration and improving o

关 键 词：长7段 致密砂岩储层 孔喉结构 非均质性 可动流体饱和度 鄂尔多斯盆地 

分 类 号：P618.130.21[天文地球—矿床学]