盘县煤田滑脱构造特征及其研究意义

Characteristics of Detachment Structures and Research Significance in Panxian Coal Field

通过对盘县煤田开展地质调查,发现煤田内发育滑脱构造层。为了探究研究区内滑脱构造的特征、样式,采用野外地质调查、剖面测量、矿井地质调查、地质钻探、钻孔岩心编录、显微煤岩分析等技术手段,综合分析滑脱构造发育的部位、空间赋存特征及构造样式。根据滑脱构造样式分析了不同构造样式下盆地内资源勘查工程部署原则、层位选择、钻探技术难点以及与瓦斯等隐蔽致灾因素的关系。研究表明:滑脱构造主要发育于三叠系飞仙关组中下部和二叠系龙潭组中部的12~18煤层间,厚20~60m,地层破碎,其间煤层为构造煤,伴随发育揉皱。滑脱构造样式有逆冲推覆、顺煤层型滑脱、顺峨眉山玄武岩型滑脱、雁列式断裂型、断层相关褶皱五种类型。滑脱构造层与盆地内“三软”煤层、突出煤层、高瓦斯煤层以及构造应力集中涉及矿井安全生产隐蔽致灾因素具有高度耦合性,表现为发育滑脱构造的部位不仅是目前盆地内煤层气含量高、矿井煤与瓦斯突出事故频发的层位,是优质煤炭资源的产出层位,也是煤矿“三软”煤层顶板事故的重点管理层位。研究成果为煤与煤层气资源勘探、开采以及矿井安全生产、隐蔽致灾因素排查治理提供基础地质资料。

Through geological investigation of the Panxian coalfield,it was found that detachment structural layers developed in the coalfield.In order to explore the characteristics and styles of detachment structures in the study area,technical means such as field geological survey,profile survey,mine geological survey,geological drilling,borehole core logging,and microscopic coal and rock analysis were used to comprehensively analyze the location,spatial occurrence characteristics,and structural styles of the development of detachment structure.Based on the styles of detachment structures,the paper analyzes the deployment principles,layer selection,drilling technical difficulties,and the relationship with hidden disaster factors such as gas under different structural styles.The research shows that the detachment structure is mainly developed between the 12~18 coal seams in the middle and lower part of Feixianguan Formation of Triassic and the middle part of Longtan Formation of Permian,with a thickness of 20~60m and a broken stratum.The coal seams are structural coal,accompanied by crumple.There are five types of detachment structures:thrust nappe,coal seam type detachment,Emeishan basalt type detachment,echelon fault type,and fault related folds.The detachment structure layer has a high coupling with the “three soft” coal seams,outburst coal seams,high gas coal seams,and structural stress concentration in the basin,which involve hidden disaster factors in mine safety production.The position where the detachment structure is developed is not only the layer with high coalbed methane content and frequent occurrence of coal and gas outburst accidents in the basin,but also the output layer of high-quality coal resources,It is also the key management level for roof accidents in the “three soft” coal seams in coal mines.The research results provide basic geological data for the exploration and exploitation of coal and coalbed methane resources,as well as for the safe production of coal mines,and the investigation and treatment of hidden disaster causing factors.