致密砂砾岩储层孔隙结构对比及差异机制研究  

Pore structure comparison and difference mechanism betweentight sandstone and tight conglomerate reservoirs

作　　者：孙灵辉[1,2] 萧汉敏[1,2] 谭龙[3] 李博文 孙东盟 王鹏威[5] SUN Linghui;XIAO Hanminl;TAN Long;LI Bowen;SUN Dongmeng;WANG Pengwei(PetroChina Research Institute of Exploration&Development,Beijing 100083,China;Instituteof Porous Flow&Fluid Mechanics,Chinese Academy of Sciences,Beijing 100083,China;Research Institule of Exploration&Development,Xinjiang Oilfield Company Petro China,Kramay,Xinjiang 834000,China;University of Chinese Academy of Sciences,Beijing 100190,China;China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国科学院渗流流体力学研究所,北京100083 [3]新疆油田公司勘探开发研究院,新疆克拉玛依834000 [4]中国科学院大学,北京100190 [5]中国石油大学(北京),北京102249

出　　处：《地质学报》2022年第6期2155-2172,共18页Acta Geologica Sinica

基　　金：国家重大科技专项(编号2016ZX05010-004);中石油科技攻关项目(编号kt2019-11-01)联合资助的成果。

摘　　要：致密储层孔隙结构研究对于致密油气的勘探和开发具有重要意义,也是当前致密储层研究的热点。本文以准噶尔盆地三叠系百口泉组致密砾岩和鄂尔多斯盆地三叠系延长组致密砂岩为研究对象,重点开展二维大面积背散射扫描电镜成像技术(Maps)、高压压汞、微米CT和聚焦离子束扫描电镜技术(FIB-SEM)等分析测试,采用定性和定量相结合的方法对致密砾岩和致密砂岩孔隙结构特征进行表征和对比,并进一步揭示了两者的成因机制差异。研究结果表明:百口泉组致密砾岩较延长组致密砂岩储层物性好,前者孔隙度和渗透率平均为9.29%和1.65×10^(-3)μm^(2),后者孔隙度和渗透率平均为8.85%和0.39×10^(-3)μm^(2)百口泉组致密砾岩较延长组致密砂岩孔喉尺寸偏大、孔隙连通性较差及孔隙结构更为复杂,前者孔喉半径主要分布在0~200 nm和2~10μm范围内,平均连通率60.63%,平均孔喉配位数3.0446,后者孔喉半径主要分布于0~4μm范围内,平均连通率73.60%,平均孔喉配位数2.7832;差异化沉积作用和成岩作用是导致百口泉组致密砾岩和延长组致密砂岩孔隙结构特征差异的根本原因。The research on pore structure of tight reservoirs is of great significance for the exploration and development of tight oil and gas,and it is also a hotspot in the research on tight reservoirs.Taking the tight conglomerates of the Triassic Baikouquan Formation in the Junggar basin and tight sandstones of the Triassic Yanchang Formation in the Ordos basin as examples,the pore structure characteristics and comparisons of tight conglomerates and tight sandstones are studied qualitatively and quantitatively,and the differences of genetic mechanism between them are further explored using two-dimensional large area backscatter scanning electron microscopy(maps),high-pressure mercury intrusion porosimetry(HMIP),micro CT and focused ion beam scanning electron microscopy(FIB-SEM).Results show that the physical properties of tight conglomerate in the Baikouquan Formation are better than those of tight sandstone in the Yanchang Formation,and the average porosity and permeability of the former is 9.29%and 1.65×10^(-3)μm^(2),while that of the latter is 8.85%and 0.39×10^(-3)μm^(2).The pore throat distribution of tight conglomerates in the Baikouquan Formation and tight sandstone in the Yanchang Formation is characterized by multi-scale continuous distribution.The pore structure of tight conglomerates in the Baikouquan Formation is characterized by pore throat radius mainly in the range of 0~200 nm and 2~10μm,average connectivity of 60.63%and average pore-throat coordination number of 3.0446.The pore structure of tight sandstones in the Yanchang Formation is characterized by pore throat radius mainly in the range of 0~4μm,average connectivity of 73.60%and average pore-throat coordination number of 2.7832.Compared with the tight sandstones of the Yanchang Formation,the tight conglomerates of the Baikouquan Formation have larger pore throat size,poor pore throat sorting,poor pore connectivity and more complex pore structure.Differential sedimentation and diagenesis are the main reasons for the pore structure differences be

关 键 词：孔隙结构 成岩作用 对比研究 致密砂砾岩 百口泉组 延长组 

分 类 号：P618.13[天文地球—矿床学]