Full-range pore throat radius distribution and fractal characteristics of different types of reservoirs in deep carbonate gas reservoirs: A case study of Deng-4 Member in Gaoshiti-Moxi Area, Sichuan Basin

被引:0
作者
Zou, Rui [1 ]
Wang, Lu [1 ]
Luo, Ruilan [2 ]
Zhang, Lin [2 ]
Deng, Hui [3 ,4 ]
Meng, Zhan [5 ]
Zou, Run [1 ]
Zhang, Yifan [1 ]
机构
[1] College of Energy, Chengdu University of Technology, Sichuan, Chengdu
[2] Petro China Research Institute of Petroleum Exploration and Development, Beijing
[3] Exploration and Development Research Institute, PetroChina Southwest Oil Gas field Company, Sichuan, Chengdu
[4] Sichuan Petroleum Administration Co., Ltd., Sichuan, Chengdu
[5] School of Petroleum and Natural Gas Engineering, Southwest Petroleum University, Sichuan, Chengdu
来源
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | 2024年 / 53卷 / 06期
关键词
constant-rate mercury injection; deep carbonate gas reservoirs; fractal characteristics; full-range pore throat radius distribution; high-pressure mercury injection; pore throat structure;
D O I
10.13247/j.cnki.jcumt.20240059
中图分类号
学科分类号
摘要
The typical characteristics of deep carbonate gas reservoirs with diverse reservoir media and complex pore throat structure in deep carbonate reservoirs make it difficult to reveal their full-range pore throat distribution and fractal characteristics. Therefore, the high-pressure mercury injection and constant-rate mercury injection experiments were jointly applied to quantitatively characterize the full-range pore throat size distribution of various reservoir types in deep carbonate gas reservoirs in Sichuan Basin. Subsequently, the complexity and micro-heterogeneity of pore throat structures at different scales were revealed through fractal theory. Finally, the relationship between fractal dimension and storage and percolation capacities was revealed, and the controlling factors of fractal dimension were analyzed. The results show that the full-range pore throat radius of four types of reservoirs in deep carbonate reservoirs is in the range of 3. 6 nm and 500 μm, and all distribution curves have multi-peak characteristics. Deep carbonate gas reservoirs mainly develop nano-scale pore throats, but the differences in micro-scale pore throats are obvious. The average values of total fractal dimension ( DT ) of fracture-cavity type, cavity type, fracture type and pore type reservoirs are 2.438, 2.509, 2. 762 and 2.804, respectively, reflecting the differences in micro-heterogeneity among different types of reservoirs. All four types of reservoirs have triple fractal characteristics of small pore-fine throat section (r<0. 027 μm), moderate pore, coarse throat section (0. 027 ≤r≤ 3.431 μ), and large pore, fracture section (r>3. 431 μm). Moreover, the differences between different types of reservoirs are mainly reflected in the small pore-fine throat section, resulting in the micro-heterogeneity of the reservoir being mainly affected by the proportion of pore throat volume and the value of fractal dimension in this section. The fractal dimension of nano-scale pore throats is lower than that of micro-scale pore throats, indicating that the heterogeneity and complexity of micro-scale pore throats are stronger than those of nano-scale pore throats under the effects of fractures and cavities. The correlation between DT and porosity, displacement pressure, skewness, maximum mercury saturation, and sorting coefficient is good, and the correlation between the fractal dimensions of nano-scale pore throats and small pore-fine throat sectionis relatively strong with these structural parameters, indicating that the small pore-fine throats at the nano-scale has a greater impact on the overall pore throat connectivity and heterogeneity of deep carbonate gas reservoirs. © 2024 China University of Mining and Technology. All rights reserved.
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页码:1218 / 1236
页数:18
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