Multifractal Characteristics and Genetic Mechanisms of Pore Throat Structures in Coal Measure Tight Sandstone

• Published in: Natural resources research (New York, N.Y.) Vol. 31; no. 5; pp. 2885 - 2900
• Main Authors: Miao, Zhang, Jindong, Wang, Xuehai, Fu, Haifeng, Lu, Zhiyong, Dong, Lirong, Li, Hao, Wang
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2022; Springer Nature B.V
• Subjects: Adsorption; Carboniferous; Chemistry and Earth Sciences; Clay minerals; Coal; Coalbed methane; Computer Science; Earth and Environmental Science; Earth Sciences; Fault lines; Fossil Fuels (incl. Carbon Capture); Fractals; Geography; Geology; Heterogeneity; High pressure; Mathematical Modeling and Industrial Mathematics; Mercury; Mineral Resources; Natural gas reserves; NMR; Nuclear magnetic resonance; Oil reserves; Original Paper; Parameters; Permeability; Permian; Physical properties; Physics; Pore size; Porosity; Quartz; Reservoirs; Sandstone; Statistics for Engineering; Sustainable Development; Sustainable production; Tectonics; Pore throat structure; Heterogeneity; Coal measures sandstones; Genetic mechanism; Qinshui basin
• ISSN: 1520-7439; 1573-8981
• DOI: 10.1007/s11053-022-10106-y

The pore structure heterogeneity of ultra-low tight sandstone has a direct impact on the exploration development and sustainable production of tight sandstone gas. In this study, high pressure mercury injection and casting thin sections methods were conducted to study the physical properties and pore structures of Carboniferous–Permian (C–P) tight sandstone reservoirs. Then, the multifractal behaviors of the pore structures and their genetic mechanisms were revealed by establishing the relationships of the multifractal parameter (spectral width of singular spectrum Δα ( Δα  =  α -10 – α 10+ )) with the petrophysical properties and the lithologic characteristics parameters. The results showed that the multifractal characteristics of the pore throat structure in the C–P sandstone were objective and that the C–P sandstone reservoir of higher mesopores volume tended to display greater pore structure heterogeneity. Moreover, the C–P tight sandstone samples with high debris and less content levels of quartz and feldspar showed stronger pore structure heterogeneity. Furthermore, there was a negative correlation between pore structure heterogeneity and interstitial material while increases in matrix (clay minerals) content and decreases in carbonate and quartz cement had potentially led to the enhancement of pore structure heterogeneity. Additionally, the double effects of tectonic stress caused some of the C–P sandstone samples to display characteristics of strong heterogeneity, low porosity and low permeability.