影响正明矿15号煤层瓦斯赋存规律的主控地质因素研究

Study on the Main Controlling Geological Factors Affecting Gas OccurrenceRule in No.15 Coal Seam of Zhengming Coal Mine

文章在收集正明矿矿井地质、矿井开采、地面煤层气勘探开发及测试参数等资料基础上,运用瓦斯地质理论对影响左权正明矿15号煤层瓦斯赋存规律的主控因素进行了研究。结果表明:地质构造、围岩、热演化及煤变质作用、煤层埋深及地下水活动是控制研究区15号煤层瓦斯赋存规律的主控地质因素。区域构造为煤层瓦斯赋存提供了良好的封闭边界,井田构造因构造类型和受力状态的差异对煤层瓦斯赋存起到封闭和逸散双重控制作用,对煤层瓦斯不均衡分布起到关键控制作用;围岩中泥质类岩石较发育,因其致密、完整、低透气性等性能对煤层瓦斯起到良好的封盖作用,控制着煤层瓦斯赋存的整体分布规律;热演化及煤的高变质,为煤层瓦斯的生成提供了良好的生烃动力和条件,是煤层瓦斯含量高低整体分布的直接控制地质因素;煤层埋深条件下,应力场正效应占主导作用,使得煤层埋深与瓦斯含量二者具有较好的线性正相关关系;地下水的弱径流、滞缓状态和承压性质对煤层瓦斯起到一定的封存和封堵效应,均不利于瓦斯的逸散散失。研究结果以期为区内矿井瓦斯防治提供技术支撑和有益技术参数。

Based on the data of mine geology,mine mining,ground coalbed methane exploration and development and test parameters,this paper studies the main factors influencing the occurrence of gas in the No. 15 coal seam of Zuoquanzheng Min Mine by using gas geological theory. The results show that the geological structure,surrounding rock,thermal evolution and coal metamorphism,coal seam depth and groundwater activity are the main controlling geologic factors controlling the occurrence of gas in the No. 15 coal seam. The regional structure provides a good closed boundary for the coal seam,and the difference between the structural type and the stress state of the coal field plays a key role in blocking and dissipating coal seam gas and plays a key role in the unbalanced distribution of coal gas Control; The muddy rocks in the surrounding rock are more developed,and the coal seam gas plays a good sealing effect because of its compact,complete and low permeability,which controls the overall distribution of coal gas. Thermal evolution and high metamorphism of coal,which provides good hydrocarbon generation and conditions for the formation of coal seam gas and is the direct controlling geological factor of the overall distribution of coal gas content. Under the conditions of seam depth,the positive effect of stress field plays a dominant role,which makes the coal seam depth and gas content have good linear positive correlation. Groundwater weak runoff,slow state and pressure nature of the coal seam to play a certain storage and sealing effect,are not conducive to the loss of gas dissipation.The results of the study will provide technical support and beneficial technical parameters for the mine gas control in the region.