Abstract:

Based on the observation and study of the samples of 3^#  and 15^#  coal seams in ten coal mines in the south of Qinshui Basin with optical microscope and scan electron microscope, the authors expound the characteristics of coal microfracture and its correlations with coal maceral composition. The study shows that the fractures are commonly present in both 3^# and 15^# coal seams. They are more developed in 15^# coal seam than in 3^# coal seam, but some fractures in 15^#  coal seam are filled. Fractures, including endogenic fracture and exogenous fracture, are mostly developed in vitrinite, among which telocollinite is primary and desmocollinite the second. In inertinite, fractures are primarily developed in fusinite and are mainly of tensional fractures. Endogenic fractures are not developed in inertinite of high rank coal. The fracture is controlled by coal maceral composition in the procedure of coalification through the release of water adopted in paludification, the combined action of composition structure and generated gas, and mechanical behaviors.

Key words: microfracture, coal maceral composition, Qinshui Basin, 3^#  coal seam, 15^# coal seam

摘要：

利用光学显微镜、扫描电镜对沁水盆地南部10个煤矿的3^#煤与15^#煤样品进行观察与研究，探讨了微裂隙的特征及其与煤岩组分的关系。研究发现微裂隙在3^#煤与15^#煤中普遍存在，15^#煤裂隙较3#煤发育，但15#煤中的裂隙被矿物充填较严重。微裂隙在镜质组内最为发育，内生裂隙和外生裂隙均有发育，均质镜质体中的裂隙最为密集，其次是基质镜质体，其他显微组分中裂隙发育较少甚至不发育；惰质组中的裂隙主要发育于丝质体中，主要为外生裂隙中的张性裂隙，内生裂隙在高煤阶煤的惰质组中不发育。煤岩组分对煤中微裂隙的控制主要体现在成煤作用过程中，包括不同组分在泥炭化作用中吸收的水再释放、组分结构与生气量的综合作用及力学性质3个方面。

关键词: 微裂隙, 煤显微组分, 沁水盆地, 3^#煤, 15^#煤