Key Controlling Factors of Deep Coalbed Methane Reservoir Characteristics in Yan’an Block, Ordos Basin: Based on Multi-Scale Pore Structure Characterization and Fluid Mobility Research
Abstract
1. Introduction
2. Regional Geological Background
2.1. Location and Structural Characteristics of the Study Area
2.2. Target Coal Seam and Burial Characteristics
2.3. Coal Petrology and Thermal Evolution Characteristics
3. Materials and Methods
3.1. Basic Properties of Coal Samples
3.2. Multi-Scale Pore Structure Characterization
3.2.1. High Pressure Mercury Intrusion Experiment (MIP)
3.2.2. Low Temperature Liquid Nitrogen Adsorption Experiment (LT-N2GA)
3.2.3. Low Temperature Carbon Dioxide Adsorption Experiment (LP-CO2GA)
3.3. Low-Field Nuclear Magnetic Resonance Fluid Mobility Test
3.4. Microscopic Morphology and Pore Visualization
3.5. Data Analysis and Integration
3.5.1. Full Aperture Distribution Reconstruction
3.5.2. Quantitative Characterization of Fractal Dimension
3.5.3. Correlation Analysis of Statistical Methods
3.5.4. Medium Hole Tortuosity and Seepage Porosity
4. Result
4.1. Coal Sample Characteristics
4.2. Classification of Pore Structure
4.3. Nuclear Magnetic Resonance Fluid Mobility
5. Discussion
5.1. Synergistic Control of Gas Occurrence-Migration by Multi-Scale Pore Network
5.2. Fractal and Connectivity Quantification of Pore Structure
5.3. Nuclear Magnetic Resonance Fluid Mobility Response
5.4. Pore-Permeability–Gas Synergistic Relationship
6. Conclusions
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Parameter | Yan’an Block | Daning-Jixian Area | South Yanchuan Block |
---|---|---|---|
Target coal seam | Shanxi group 5 #, Benxi group 8 # coal | Shanxi group 5 # coal | Shanxi group 5 #, Benxi group 8 # coal |
Buried depth range (m) | 2200–3000 | 1500–2200 | 1800–2500 |
The average thickness of 5 # coal (m) | 3.5 | 4.2 | 3.6 |
The average thickness of 8 # coal (m) | 2.2 | - | 2.3 |
Ro,max (%) | >2.0 | 1.8–2.2 | 2.0–2.5 |
Geothermal gradient (°C/100 m) | 2.8 | 3.0 | 2.9 |
Specimen | Density g/cm3 | Vitrinite Reflectivity Ro,max | Coal Maceral Content/% | Industrial Analysis/% | ||||
---|---|---|---|---|---|---|---|---|
Vitrinite/% | Inertinite/% | Lipid Group and Mineral Composition/% | Mad | Aad | Vdaf | |||
Y2015-B1-4 | 1.66 | 4.06 | 85.9 | 12.8 | 1.3 | 1.42 | 9.56 | 5.71 |
Y2015-B1-2 | 1.56 | 4.38 | 85.3 | 13.6 | 1.1 | 0.93 | 6.78 | 5.92 |
Y1560-B1-1 | 1.87 | 2.04 | 62.7 | 32.7 | 4.6 | 0.54 | 46.39 | 22.54 |
Y1557-S2-3 | 1.44 | 1.86 | 51.3 | 41.7 | 7 | 0.58 | 12.94 | 14.33 |
Sample Number | Full Aperture Pore Volume (mL/g) | Full Aperture Specific Surface Area (m2/g) | ||||||
---|---|---|---|---|---|---|---|---|
Total Pore Volume | Micropore | Mesopore | Macropore | Total Surface Area | Micropore | Mesopore | Macropore | |
Y855 | 0.2396 | 0.0690 | 0.0020 | 0.1686 | 238.0980 | 231.2580 | 0.8190 | 6.0210 |
Y2085 4 | 0.2036 | 0.0590 | 0.0010 | 0.1436 | 199.2550 | 192.7640 | 0.1590 | 6.3320 |
Y2085 5 | 0.1460 | 0.0770 | 0.0020 | 0.0670 | 267.9600 | 264.8420 | 0.5840 | 2.5340 |
Y2030 | 0.0913 | 0.0470 | 0.0220 | 0.0223 | 152.7620 | 143.8560 | 6.1730 | 2.7330 |
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Sun, J.; Han, S.; Liu, S.; Lin, J.; Li, F.; Liu, G.; Shi, P.; Teng, H. Key Controlling Factors of Deep Coalbed Methane Reservoir Characteristics in Yan’an Block, Ordos Basin: Based on Multi-Scale Pore Structure Characterization and Fluid Mobility Research. Processes 2025, 13, 2382. https://doi.org/10.3390/pr13082382
Sun J, Han S, Liu S, Lin J, Li F, Liu G, Shi P, Teng H. Key Controlling Factors of Deep Coalbed Methane Reservoir Characteristics in Yan’an Block, Ordos Basin: Based on Multi-Scale Pore Structure Characterization and Fluid Mobility Research. Processes. 2025; 13(8):2382. https://doi.org/10.3390/pr13082382
Chicago/Turabian StyleSun, Jianbo, Sijie Han, Shiqi Liu, Jin Lin, Fukang Li, Gang Liu, Peng Shi, and Hongbo Teng. 2025. "Key Controlling Factors of Deep Coalbed Methane Reservoir Characteristics in Yan’an Block, Ordos Basin: Based on Multi-Scale Pore Structure Characterization and Fluid Mobility Research" Processes 13, no. 8: 2382. https://doi.org/10.3390/pr13082382
APA StyleSun, J., Han, S., Liu, S., Lin, J., Li, F., Liu, G., Shi, P., & Teng, H. (2025). Key Controlling Factors of Deep Coalbed Methane Reservoir Characteristics in Yan’an Block, Ordos Basin: Based on Multi-Scale Pore Structure Characterization and Fluid Mobility Research. Processes, 13(8), 2382. https://doi.org/10.3390/pr13082382