基于原子力显微镜的煤岩微观孔隙结构与力学性质研究

赵石虎; 李勇; 刘雅利; 王延斌; 刘曾勤; 陈刚; 陈新军

doi:10.11781/sysydz2025010173

基于原子力显微镜的煤岩微观孔隙结构与力学性质研究

doi: 10.11781/sysydz2025010173

赵石虎^{1, 2, 3, 4,},
李勇^5, ,,
刘雅利^{1, 2, 3, 4},
王延斌⁵,
刘曾勤^{1, 2, 3, 4},
陈刚^{1, 2, 3, 4},
陈新军^{1, 2, 3, 4}

1.
页岩油气富集机理与高效开发全国重点实验室，北京 102206
2.
中国石化页岩油气勘探开发重点实验室，北京 102206
3.
中国石化深层煤层气勘探开发重点实验室，北京 102206
4.
中国石化石油勘探开发研究院，北京 102206
5.
中国矿业大学(北京)，北京 100083

基金项目:

中国石化科技部项目 P23206

中国石化科技部项目 P23230

中国石化石油勘探开发研究院优青项目 YK202406

详细信息

作者简介:
赵石虎(1992—)，男，博士，从事煤层气地质研究工作。E-mail: zhaoshh0310.syky@sinopec.com

通讯作者:
李勇(1988—)，男，博士，教授，博士生导师，从事煤与煤层气地质、煤系矿产资源方面的教学和科研工作。E-mail: liyong@cumtb.edu.cn

中图分类号: TE132.2
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出版历程
- 收稿日期: 2023-12-07
- 修回日期: 2024-11-29
- 刊出日期: 2025-01-28

Study on microscopic pore structures and mechanical properties

ZHAO Shihu^{1, 2, 3, 4
,},
LI Yong^{5
, ,},
LIU Yali^{1, 2, 3, 4},
WANG Yanbin⁵,
LIU Zengqin^{1, 2, 3, 4},
CHEN Gang^{1, 2, 3, 4},
CHEN Xinjun^{1, 2, 3, 4}

1.
State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 102206, China
2.
SINOPEC Key Laboratory of Shale Oil and Gas Exploration and Production, SINOPEC, Beijing 102206, China
3.
SINOPEC Key Laboratory of Deep Coalbed Methane Exploration and Development, Beijing 102206, China
4.
SINOPEC Petroleum Exploration and Production Research Institute, Beijing 102206, China
5.
China University of Mining and Technology (Beijing), Beijing 100083, China

摘要

摘要: 煤岩孔隙结构与力学性质是煤层气地质评价的关键参数，反映煤的储集性与可压性。以山西沁水、大同等盆地4块煤样(大同侏罗系煤、镜质体反射率R_o=0.91%，古交山西组2号煤、R_o=1.34%，古交太原组8号煤、R_o=1.70%，翼城山西组2号煤、R_o= 1.77%)为研究对象，基于原子力显微镜实验，利用图像分割法与Derjaguin-Muller-Toporov力学模型建立微观孔隙结构与力学性质联合表征技术，明确煤样的微观孔隙结构与力学性质，揭示了物质组成、孔隙结构及热演化程度对微观力学性质的影响。结果表明，煤样的面孔率主要分布于2.72%~4.60%，平均3.58%；总孔表面积为(3.413~5.638)×10^-2 μm²/μm²，总孔容为(0.5~3.9)×10^-4 μm³/μm²，孔径主要分布于10~100 nm，杨氏模量分布于2.24~3.10 GPa，平均2.77 GPa。煤的力学性质受到物质组成、孔隙结构与热演化程度的共同作用，随着水分的减少、挥发分与矿物含量的增加，杨氏模量呈现增大趋势；表面粗糙度、平均孔径、面孔率、比表面积及总孔容增大，杨氏模量表现出减小趋势；随着热演化程度增加，杨氏模量减小。基于原子力显微镜可同步揭示煤岩微观孔隙结构与力学性质，为煤储层储集性与力学研究提供新方法与新思路，对于非常规储层储集性评价及可压性研究具有重要意义。
- 表面粗糙度 /
- 孔径分布 /
- 杨氏模量 /
- 原子力显微镜 /
- 图像分割 /
- 煤层气
Abstract: The pore structures and mechanical properties of coal are key parameters for geological evaluation of coalbed methane, reflecting its reservoir capacity and compressibility. The study investigated four coal samples from the Qinshui and Datong basins in Shanxi Province, including Jurassic coal from Datong (R_o=0.91%), No. 2 coal from the Shanxi Formation in Gujiao (R_o=1.34%), No. 8 coal of the Taiyuan Formation in Gujiao (R_o=1.70%), and No. 2 coal of the Shanxi Formation in Yicheng (R_o=1.77%). Using atomic force microscopy (AFM), a combined characterization technique was established for microscopic pore structure and mechanical properties based on image segmentation and Derjaguin-Muller-Toporov (DMT) mechanical model. This method clarified the microscopic pore structure and mechanical properties of coal samples and revealed the influence of material composition, pore structure, and thermal evolution level on their microscopic mechanical properties. The results showed that the surface porosity of coal samples mainly ranged from 2.72% to 4.60%, with an average of 3.58%. The total pore surface area and total pore volume were (3.413-5.638)×10^-2 μm²/μm² and (0.5-3.9)×10^-4 μm³/μm², respectively. The pore sizes were mainly distributed between 10-100 nm, and the Young's modulus ranged from 2.24 to 3.10 GPa, with an average of 2.77 GPa. The mechanical properties of coal were influenced by the material composition, pore structure, and thermal evolution level. As moisture decreased and volatile and mineral content increased, the Young's modulus showed an increasing trend. With an increase in surface roughness, mean pore size, porosity surface, specific surface area, and total pore volume, the Young's modulus decreased. As thermal evolution progressed, the Young's modulus decreased. AFM enables simultaneous analysis of microscopic pore structure and mechanical properties of coal, providing new methods and insights for studying reservoir capacity and mechanical behavior of coal reservoirs. It holds significant implications for the evaluation of reservoir capacity and compressibility in unconventional reservoirs.
- surface roughness /
- pore size distribution /
- Young's modulus /
- atomic force microscope /
- image segmentation /
- coalbed methane
注释:

利益冲突声明/Conflict of Interests

所有作者声明不存在利益冲突。

All authors declare no relevant conflict of interests.

作者贡献/Authors’Contributions

赵石虎，李勇，王延斌参与实验设计；赵石虎，陈新军完成实验操作；赵石虎，刘雅利完成实验分析；赵石虎，刘雅利，刘曾勤，陈刚参与论文写作和修改。所有作者均阅读并同意最终稿件的提交。

The experiments were designed by ZHAO Shihu, LI Yong, and WANG Yanbin. The experimental operations were completed by ZHAO Shihu and CHEN Xinjun. The experimental analysis was completed by ZHAO Shihu and LIU Yali. The manuscript was drafted and revised by ZHAO Shihu, LIU Yali, LIU Zengqin, and CHEN Gang. All authors have read the final version of the paper and consented to its submission.

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图 1 原子力显微镜基本原理与仪器

据参考文献[22]修改。

Figure 1. Basic principle and device of atomic force microscope

下载: 全尺寸图片幻灯片

图 2 针尖与样品力—位移曲线

据参考文献[24]修改。

Figure 2. Force and displacement curves between needle tip and sample

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图 3 煤样AFM表面形貌

a、b、c、d分别为样品XZ-1、GJ2-1、GJ8-1、SH-1的表面形貌二维图；e、f、g、h分别为样品XZ-1、GJ2-1、GJ8-1、SH-1的表面形貌剖面图。

Figure 3. AFM surface morphologies of coal samples

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图 4 基于AFM形貌图的不同地区煤样分形特征

a. XZ-1样品; b. GJ-2样品; c. GJ-8样品; d. SH-1样品。

Figure 4. Fractal characteristics of coal samples from different regions based on AFM morphologies

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图 5 基于阈值分水岭结合法的AFM图孔隙表征结果

a. XZ-1样品; b. GJ-2样品; c. GJ-8样品; d. SH-1样品。

Figure 5. Pore characterization results of AFM images based on combination of threshold and watershed methods

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图 6 基于AFM的不同地区煤样孔径分布

a. 孔隙数量分布; b.孔容占比分布; c. 孔表面积分布。

Figure 6. Pore size distributions of coal samples from different regions based on AFM

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图 7 基于AFM的微观DMT杨氏模量

a. XZ-1样品煤基质; b. GJ2-1样品煤基质; c. GJ8-1样品煤基质; d. SH-1样品煤基质; e. SH-1样品矿物; f. GJ2-1样品矿物。

Figure 7. Micro DMT Young's modulus of coal samples based on AFM

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图 8 不同地区煤基质与矿物杨氏模量统计

a. XZ-1样品煤基质; b. GJ2-1样品煤基质; c. GJ8-1样品煤基质; d. SH-1样品煤基质; e. SH-1样品矿物; f. GJ2-1样品矿物。

Figure 8. Young's modulus statistics of coal matrix and minerals from different regions

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图 9 GJ2-1煤样孔隙结构(a)和杨氏模量表征结果(b)与扫描电镜图像(c)对比

Figure 9. Comparison of characterization results of pore structure (a) and Young's modulus (b) with scanning electron microscopy images (c) of GJ2-1 coal samples

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图 10 煤的工业组分与DMT杨氏模量相关关系

a. M_ad与杨氏模量关系; b. A_ad与杨氏模量关系; c. V_ad与杨氏模量关系; d. FC_ad与杨氏模量关系。

Figure 10. Correlation between industrial components of coal and DMT Young's modulus

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图 11 微观孔隙结构参数与DMT杨氏模量相关关系

a.R_a与杨氏模量关系; b.分形维数与杨氏模量关系; c.平均孔径与杨氏模量关系; d.面孔率与杨氏模量关系; e.总孔容与杨氏模量关系; f.总孔表面积与杨氏模量关系。

Figure 11. Correlation between microscopic pore structure parameters and DMT Young's modulus

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图 12 煤的镜质体反射率与DMT杨氏模量相关关系

Figure 12. Correlation between vitrinite reflectance of coal and DMT Young's modulus

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表 1 不同地区煤样工业组分及演化程度参数

Table 1. Parameters of industrial components and thermal evolution levels of coal samples from different regions

样品来源	样品编号	R_o/%	工业组分含量/%
样品来源	样品编号	R_o/%	M_ad	A_ad	V_ad	FC_ad
忻州窑侏罗系煤	XZ-1	0.91	0.78	25.40	25.02	48.80
原相矿区2号煤	GJ2-1	1.34	2.35	16.24	14.45	66.95
原相矿区8号煤	GJ8-1	1.70	0.86	13.65	17.81	67.68
上河矿区2号煤	SH-1	1.77	0.77	6.47	15.24	77.52
注：R_o.镜质体反射率；M_ad.空气干燥基水分；A_ad.空气干燥基灰分；V_ad.空气干燥基挥发分；FC_ad.空气干燥基固定碳。

下载: 导出CSV

表 2 不同地区煤样表面粗糙度评价结果

Table 2. Evaluation results of surface roughness of coal samples from different regions

样品编号	R_o/%	R_a/nm	R_q/nm	R_sk	R_ku
XZ-1	0.91	0.73	0.97	0.50	0.83
GJ2-1	1.34	1.34	1.87	1.94	21.18
GJ8-1	1.70	0.78	1.01	0.16	0.76
SH-1	1.77	0.95	1.45	0.72	6.08

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表 3 煤样孔隙结构评价结果

Table 3. Evaluation results of pore structures of coal samples

样品编号	孔隙数量/个	面孔率/%	平均孔径/nm	总孔表面积/(μm²/μm²)	总孔容/(μm³/μm²)
XZ-1	338	2.72	103	3.413	0.005
GJ2-1	637	4.60	104	5.638	0.039
GJ8-1	352	4.03	129	5.259	0.011
SH-1	467	2.95	94	3.631	0.023

下载: 导出CSV

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