刘佳佳，张云龙，杨迪，等.基于压汞-氮吸附-核磁共振法的中低阶煤孔裂隙联合表征［J］.河南理工大学学报（自然科学版），doi:10.16186/j.cnki.1673-9787.2024010059

LIU J J，ZHANG Y L，YANG D，et al.Joint characterization of middle and low rank coal pores and fractures based on pressed mercury-nitrogen adsorption-nuclear magnetic resonance method［J］.Journal of Henan Polytechnic University（Natural Science），doi: 10.16186/j.cnki.1673-9787. 2024010059

基于压汞-氮吸附-核磁共振法的中低阶煤孔裂隙联合表征(网络首发)

刘佳佳^{1，2，3，4}，张云龙¹，杨迪¹，高志扬^1，3，4，王丹^3，4

（1.河南理工大学，安全科学与工程学院，河南 焦作 454000；2.安徽理工大学 深部煤矿采动响应与灾害防控国家重点实验室，安徽 淮南 232001；3.河南理工大学 煤炭安全生产与清洁高效利用省部共建协同创新中心，河南 焦作454000；4.河南理工大学 河南省瓦斯地质与瓦斯治理重点实验室-省部共建国家重点实验室培育基地，河南 焦作 454000）

摘要: [目的] 为深入研究中低阶煤中孔裂隙结构和孔径分布形态， [方法] 利用压汞、低温液氮吸附和低场核磁共振试验，结合分形维数分别对新疆艾维尔沟1890煤矿（XJ）低阶煤和鹤壁八矿（HB）中阶煤的孔隙结构和孔径分布进行联合表征，并提出一种基于优势区间的全孔径分形维数表征方法，即r<140 nm的孔径分形维数使用液氮法的FHH模型表征；140~1 000 nm的孔径分形维数使用核磁共振模型表征；r>1 000 nm的孔径分形维数使用压汞法的Menger海绵模型表征。[结果] 结果表明：XJ低阶煤的中大孔主要由开放孔构成，微小孔主要由封闭孔和半封闭孔构成，其中，大孔对孔容的贡献率最高，达到94%以上，中孔是孔比表面积的主要贡献者，贡献率为40.58%，微小孔和中孔较发育，大孔几乎不发育，微小孔的孔隙连通性较差，中大孔隙的连通性较好；HB中阶煤孔隙主要由半封闭孔构成，其中孔容中大孔占比最高，占比达97%以上，孔比表面积主要由小孔贡献，贡献率为58.33%，以微小孔发育为主，中孔、大孔和裂隙相对不发育，孔隙连通性较差；液氮法的DFT模型可以得到XJ低阶煤最发育的孔径为10~12 nm，HB中阶煤最发育的孔径为1~4 nm；HB中阶煤在孔径r<140 nm内分形维数明显大于XJ低阶煤的，在此孔径范围内HB中阶煤非均质性比XJ低阶煤的更强，孔隙结构更复杂；HB中阶煤在孔径r>140 nm内的分形维数小于XJ低阶煤的，在此孔径范围内XJ低阶煤的孔隙结构比HB中阶煤更复杂。[结论] 研究成果揭示了中低阶煤储层孔隙分布规律，为中低阶煤层的裂隙扩展和瓦斯运移提供理论指导。

关键词: 中低阶煤；孔径分布；孔隙特征；分形维数；联合表征

中图分类号：TD353

doi: 10.16186/j.cnki.1673-9787.2024010059

基金项目: 国家自然科学基金资助项目（52074106）；河南省优秀青年基金资助项目（232300421061）；河南理工大学创新型科研团队项目（T2023-3）；深部煤矿采动响应与灾害防控国家重点实验室开放基金资助项目（SKLMRDPC22KF11）；河南理工大学青年骨干教师培养计划项目（2023XQG-07）

收稿日期：2024-01-25

修回日期：2024-07-17

网络首发日期：2024-10-15

Joint characterization of middle and low rank coal pores and 

fractures based on pressed mercury-nitrogen adsorption-nuclear 

magnetic resonance method

LIU Jiajia^{1，2，3，4}，ZHANG Yunlong¹，YANG Di¹，GAO Zhiyang^1，3，4，WANG Dan^3，4

（1. School of Safety Science and Engineering， Henan Polytechnic University， Jiaozuo 454000， Henan， China；2. State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines，Anhui University of Science and Technology， Huainan 232001， Anhui， China；3.Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization， Henan Polytechnic University， Jiaozuo  454000， Henan， China；4. Henan Provincial Key Laboratory of Gas Geology and Gas Control-Provincial and Ministry of State Key Laboratory Breeding Base， Henan Polytechnic University， Jiaozuo 454000， Henan， China）

Abstract: [Objective] In order to further study the pore structure and distribution of middle and low rank coal， [Methods] mercury injection， low temperature liquid nitrogen adsorption and low field nuclear magnetic resonance experiments were used to jointly characterize the pore structure and pore size distribution of the low rank coal in Aiweilgou 1890 coal Mine （XJ） and the middle rank coal in Hebi No.8 Coal Mine （HB）， combined with fractal dimension. A full-aperture fractal dimension characterization method based on dominant interval is proposed， namely： the fractal dimension of r<140 nm is characterized by FHH model using liquid nitrogen method； The fractal dimension of aperture 140~1 000 nm was characterized by NMR model. The fractal dimension of aperture r>1 000 nm was characterized by the Menger sponge model of mercury injection method. [Results] The results show that： The large and medium pores of low-rank XJ coal are mainly composed of open pores， and the small pores are mainly composed of closed and semi-closed pores. Among them， the contribution rate of large pores to pore volume is the highest， reaching more than 94%， and the contribution rate of medium pores is the main contributor of pore specific surface area， accounting for 40.58%. The small pores and medium pores are relatively developed， while the large pores are almost undeveloped， and the pore connectivity of small pores is poor. The connectivity of large pores is good. The pores of HB medium-rank coal are mainly composed of semi-closed pores， in which the proportion of large pores is the highest， accounting for more than 97% of the pore volume. The specific surface area of pores is mainly contributed by small pores， with a contribution rate of 58.33%. Small pores are mainly developed， while medium pores， large pores or cracks are relatively undeveloped， and the pore connectivity is poor. The DFT model of liquid nitrogen method shows that the most developed pore diameter of low-rank XJ coal is 10~12 nm， and that of mid-rank HB coal is 1~4 nm. The fractal dimension of HB mid-rank coal is significantly larger than that of XJ low-rank coal in the r<140 nm pore size range， and the heterogeneity of HB mid-rank coal is stronger than that of XJ low-rank coal in this pore size range， and the pore structure is more complex. The fractal dimension of the mid-rank coal of HB is smaller than that of the low-rank coal of XJ in the pore size range of r>140 nm， and the pore structure of the low-rank coal of XJ is more complex than that of the mid-rank coal of HB. [Conclusion] Research achievements provides theoretical guidance for the fracture expansion and gas migration in the middle and low-rank coal seam.

Key words: medium and low rank coal；pore size distribution；pore morphology；fractal dimension；comprehensive representation

CLC: