三塘湖盆地条湖—马朗凹陷侏罗系西山窑组巨厚煤层孔隙多尺度联合表征

陈跃; 雷琪琪; 马东民; 王馨; 王兴刚; 黄蝶芳; 荣高翔

doi:10.11781/sysydz2025010104

三塘湖盆地条湖—马朗凹陷侏罗系西山窑组巨厚煤层孔隙多尺度联合表征

doi: 10.11781/sysydz2025010104

1.
西安科技大学地质与环境学院，西安 710054
2.
中国石油吐哈油田分公司勘探开发研究院，新疆哈密 839009
3.
西安荣翔精细化工有限责任公司，西安 710000

基金项目:

国家自然科学基金项目 41902175

中国石油科技攻关项目 2021DJ2306

山西省科技厅揭榜招标项目 20201101002

详细信息

作者简介:
陈跃(1988—)，男，副教授，从事煤及煤层气地质与开发研究。E-mail: cyxust@126.com

通讯作者:
雷琪琪(1999—)，男，硕士生，研究方向为煤及煤层气开发。E-mail: 3078526201@qq.com

中图分类号: TE122.2
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出版历程
- 收稿日期: 2024-08-15
- 修回日期: 2024-12-05
- 刊出日期: 2025-01-28

Combined multi-scale characterization of pores in ultra-thick coal seams of Jurassic Xishanyao Formation, Tiaohu-Malang sags, Santanghu Basin

1.
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
2.
Research Institute of Exploration and Development, Tuha Oilfield Company, PetroChina, Hami, Xinjiang 839009, China
3.
Xi'an Rongxiang Fine Chemical Co. Ltd., Xi'an, Shaanxi 710000, China

摘要

摘要: 三塘湖盆地侏罗系西山窑组中下部巨厚煤层分布广泛，然而目前对于巨厚煤层孔隙特征的研究较少。为精细表征盆地条湖—马朗凹陷煤储层孔隙特征，以西山窑组9-1和9-2煤为研究对象，通过高压压汞、低温液氮吸附、核磁共振、CT扫描、扫描电镜等实验手段和孔隙—裂隙分析系统(PCAS)探究其孔隙发育特征。结果表明，两煤分层煤样表面形貌差异较大，9-1煤表面含有大量矿物晶体颗粒，气孔、角砾孔、摩擦孔以及微裂隙发育，孔裂隙拓扑结构明显，9-2煤具有明显的原生纤维结构，裂隙规模小而分散。两煤层孔隙结构分形特征差异明显，9-1煤比9-2煤非均质性更强，液氮吸附曲线属于Ⅱ型，存在H4型曲线滞后环。9-2煤微孔和小孔分维值分别为2.53和2.63，复杂程度更高，渗流孔连通性更强。煤样多重分形特征表明，小孔径孔隙分布较集中，分布范围较小，该孔径段非均质性更强，其中9-1煤孔径分布集中性更强，孔径分布间隔相对更均匀。采用联合表征煤样全尺度孔径分布特征，9-2煤总孔容大于9-1煤，大孔体积占比最大，分别为47.97%和44.48%，其次为中孔和小孔，微孔占比最少；微孔对两煤层孔比表面积贡献最大，分别为62.67%和58.43%；9-1煤各孔径的孔容贡献率与孔径大小呈正相关，而孔比表面积与孔径大小呈负相关。
- 煤储层 /
- 孔裂隙分析系统 /
- 多尺度孔隙 /
- 多重分形 /
- 条湖—马朗凹陷 /
- 三塘湖盆地
Abstract: The ultra-thick coal seams in the middle and lower parts of the Jurassic Xishanyao Formation in the Santanghu Basin are widely distributed. However, research on the pore characteristics of these ultra-thick coal seams is limited. To accurately characterize the porosity features of these coal reservoirs in the Tiaohu-Malang sags of the Santanghu Basin, the study examined the 9-1 and 9-2 coal samples of the Xishanyao Formation. Techniques such as high-pressure mercury intrusion porosimetry, low-temperature liquid nitrogen adsorption, nuclear magnetic resonance (NMR), CT scanning, scanning electron microscopy (SEM), and the pore-crack analysis system (PCAS) were used to investigate pore development characteristics. The results show significant differences in surface morphology between the two coal seam samples. The surface of the 9-1 coal sample contains a large number of mineral crystal particles, with well-developed pores, breccia pores, friction holes, and micro-fractures, displaying a distinct pore-fracture topological structure. The 9-2 coal sample exhibits prominent primary fibrous structures, with smaller and more dispersed fractures. The fractal characteristics of the pore structures also differ significantly between the two coal seams, with the 9-1 coal sample showing stronger heterogeneity. Its liquid nitrogen adsorption curves correspond to type Ⅱ with a H4 hysteresis loop. For the 9-2 coal sample, the fractal dimensions of micropores and small pores are 2.53 and 2.63, respectively, indicating higher complexity and better permeability connectivity. Multifractal characteristics analysis shows that pores of small diameters exhibit a more concentrated distribution and a narrower range, with stronger heterogeneity. The pore distribution of 9-1 coal sample is more concentrated, with a relatively more uniform pore size distribution intervals. Using a combined full-scale characterization method, it is revealed that 9-2 coal sample has a higher total pore volume than 9-1. Macropores have the largest volume proportion, accounting for 47.97% and 44.48%, respectively, followed by mesopores and small pores, and the proportion of micropores is the smallest. Micropores contribute the most to the pore specific surface areas for both seams, which are 62.67% and 58.43%, respectively. For the 9-1 coal sample, the pore volume contribution positively correlates with pore size, while the specific surface area contribution negatively correlates with pore size.
- coal reservoir /
- pore-crack analysis system /
- multi-scale pore /
- multifractal /
- Tiaohu-Malang sags /
- Santanghu Basin
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 disclose no relevant conflict of interests.

作者贡献/Authors’Contributions

陈跃、马东民参与论文构思；陈跃、雷琪琪参与论文写作和修改。王馨、王兴刚、黄碟芳、荣高翔负责实验设计；所有作者均阅读并同意最终稿件的提交。

The study was designed by CHEN Yue and MA Dongmin. The manuscript was drafted and revised by CHEN Yue and LEI Qiqi. The experiment was designed by WANG Xin, WANG Xinggang, HUANG Diefang, and RONG Gaoxiang. All authors have read the final version of the paper and consented to its submission.

HTML全文

图 1 三塘湖盆地构造单元划分

Figure 1. Tectonic unit division in Santanghu Basin

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图 2 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤样SEM图像和PCAS处理后图像

Figure 2. SEM images and PCAS-processed images of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 3 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤物质相模型及孔隙模型

Figure 3. Material phase models and pore models of coal samples from Jurassic Xishanyao Formation of Tiaohu-Malang sags, Santanghu Basin

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图 4 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤孔隙表面积及体积占比

Figure 4. Pore surface area and volume proportion of coal samples from Jurassic Xishanyao Formation of Tiaohu-Malang sags, Santanghu Basin

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图 5 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组不同煤样压缩性校正前后曲线

Figure 5. Pre- and post-calibration compressibility curves of different coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 6 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组压汞孔径分布及阶段孔体积变化曲线

Figure 6. Mercury intrusion pore size distribution and stage pore volume variation curves of Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 7 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤压汞测试分形维数拟合曲线

Figure 7. Fractal dimension fitting curves of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin, tested by mercury intrusion porosimetry

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图 8 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组不同煤样液氮吸(脱)附曲线

Figure 8. Liquid nitrogen adsorption/desorption curves for different coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 9 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤液氮吸附孔径分布曲线

Figure 9. Pore size distribution curves of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin, tested by liquid nitrogen adsorption experiments

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图 10 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤低温液氮实验孔隙分形特征

Figure 10. Pore fractal characteristics of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin, tested by cryogenic liquid nitrogen experiments

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图 11 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤样低场核磁共振T₂弛豫图谱

Figure 11. Low-field nuclear magnetic resonance T₂ relaxation spectra of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 12 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤配分函数双对数曲线拟合图

Figure 12. Double-logarithmic curve fitting of partition function for coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 13 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤样多重分形谱图

Figure 13. Multifractal spectra of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 14 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤全尺度孔径联合表征

Figure 14. Combined characterization of full-scale pore sizes of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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图 15 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤样全尺度孔径分布

Figure 15. Full-scale pore size distribution of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

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表 1 测试煤样的工业分析组分与显微组分

Table 1. Industrial analysis and maceral components of tested coal samples

煤样	取样点深度/m	显微组分/%				工业组分/%
煤样	取样点深度/m	水分	灰分	挥发分	固定碳	镜质组	惰质组	壳质组
9-1	1 002.2	3.44	2.51	29.64	64.41	38.40	58.40	3.2
9-2	1 034.4	3.47	2.60	34.29	59.64	41.70	54.90	3.4

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表 2 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤样PCAS分析结果

Table 2. PCAS analysis results of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

煤样	放大倍数	平均面积/nm²	平均周长/nm	平均形状系数	分形维数	面孔率/%
9-1	500	492.06	285.99	0.249 6	1.350 0	3.28
9-2	500	489.72	276.90	0.260 4	1.280 1	4.08

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表 3 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤压汞校正结果

Table 3. Mercury intrusion calibration results of coal samples from Jurassic Xishanyao Formation of Tiaohu-Malang sags, Santanghu Basin

样品	k_c/(10^-10 m²/N)	进汞量/(cm³/g)		误差/%
样品	k_c/(10^-10 m²/N)	校正前	校正后	误差/%
9-1	1.089	0.082 2	0.058 3	29.1
9-2	1.181	0.123 8	0.097 2	21.5

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表 4 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤液氮吸附测试各孔径段比表面积及孔容比例

Table 4. Specific surface area and pore volume ratio of each pore size of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin, tested by liquid nitrogen adsorption experiments

煤样	各孔径段孔容/(cm³/g)		各孔径段比例/%		各孔径段比表面积/(m²/g)		各孔径段比例/%
煤样	微孔	小孔	微孔	小孔	微孔	小孔	微孔	小孔
9-1	0.003 3	0.004 5	42.64	57.36	1.178 3	0.410 0	74.18	25.82
9-2	0.002 9	0.008 0	26.30	73.70	1.301 9	0.460 4	73.88	26.12

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表 5 三塘湖盆地条湖—马朗凹陷侏罗系西山窑组煤全尺度孔径分布

Table 5. Full-scale pore size distribution of coal samples from Jurassic Xishanyao Formation in Tiaohu-Malang sags, Santanghu Basin

煤样	孔容占比/%				孔比表面积占比/%
煤样	微孔	小孔	中孔	大孔	微孔	小孔	中孔	大孔
9-1	4.00	10.99	37.04	47.97	62.67	24.69	12.06	0.58
9-2	2.89	8.98	43.64	44.48	58.43	21.71	18.79	1.07

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