中南大学学报（自然科学版）2024，Vol.55Issue(4)：1361-1373,13.DOI:10.11817/j.issn.1672-7207.2024.04.011
致密砂岩三元孔喉结构特征:以鄂尔多斯盆地三叠系延长组7段致密砂岩为例
Ternary pore structure characteristics of the tight sandstone:a case study from the Chang 7 Member of the Triassic Yanchang Formation in the Ordos Basin,China
摘要
Abstract
The analysis of pore structure characteristics in the tight sandstone is crucial for the exploration and development of tight oil reservoirs.However,there are few studies on the differences of pore morphological characteristics at different scales,which poses great challenges to the exploration and evaluation of tight reservoirs.Thus,casting thin sections,scanning electron microscopy and mercury intrusion tests were employed to examine the pore structure characteristics of the tight sandstone from the Chang 7 Member of the Triassic Yanchang Formation in the Ordos Basin,China.The results show that the tight sandstone exhibits a ternary pore structure comprised of combined pores,particle pores and intergranular pores.Combined pores form a spiny ball model with large radius and strong connectivity.Particle pores represent a shuttlecock model with medium radius and connectivity.The intergranular pores create an envelope surface filled with particles.These intergranular pores have small radius and poor connectivity.Within the tight sandstone,residual intergranular pores and dissolution pores are the primary contributors to the reservoir space,while permeability is primarily controlled by combined pores.Due to the formation of multiple connecting channels during diagenesis,combined pores exhibit higher connectivity compared to other types of pores.A high proportion of combined pores results in a more uniform fluid flow process,leading to the formation of larger,highly oil-saturated sand bodies.The sandstones that are dominated by combine pores,undergo strong dissolution,and are located near the source rocks represent the most favorable area for the exploitation and development of tight sandstone reservoirs.Overall,the study demonstrates that morphological diversity of tight sandstone pores reveals the varied impact of different pore types on reservoir storage and connectivity.These research findings provide a geological foundation for the exploration and evaluation of tight sandstone reservoirs.关键词
致密砂岩/孔隙结构/分形/鄂尔多斯盆地Key words
tight sandstone/pore structure/fractal dimension/Ordos Basin分类
地质学引用本文复制引用
王伟,朱玉双,梁正中..致密砂岩三元孔喉结构特征:以鄂尔多斯盆地三叠系延长组7段致密砂岩为例[J].中南大学学报（自然科学版）,2024,55(4):1361-1373,13.基金项目
国家自然科学基金资助项目(42062011,42362023) （42062011,42362023）
陕西省教育厅青年项目(22JK0630) （22JK0630）
陕西省科技厅一般项目(2023-JC-QN-0347) （2023-JC-QN-0347）
中国科学院洁净能源创新研究院-榆林学院联合基金资助项目(YLU-DNL Fund 2022012)(Projects(42062011,42362023)supported by the National Natural Science Foundation of China （YLU-DNL Fund 2022012）
Project(22JK0630)supported by the Department of Education of Shaanxi Province （22JK0630）
Project(2023-JC-QN-0347)supported by the Department of Science and Technology of Shaanxi Province （2023-JC-QN-0347）
Project(YLU-DNL Fund 2022012)supported by the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy,CAS) （YLU-DNL Fund 2022012）
