开平煤田不同层次构造活动对瓦斯赋存的控制作用

Study on control action of different levels of tectonic activity on gas occurrence of Kaiping coalfield

基于对开平煤田瓦斯地质特征的研究,采用构造逐级控制理论,系统研究了不同层次构造活动对开平煤田瓦斯赋存的控制作用。结果表明:受构造演化的控制,开平向斜除NW翼大部地区煤层经历一次生气过程外,其它地区由于逆冲推覆作用和岩浆侵入的影响,发生了二次生气作用;区域上构造发育的不均一性导致瓦斯赋存的差异性,NW翼由于逆断层和水力的封堵作用,使得瓦斯保存条件较好;SE翼由于正断层和水力的逸散作用,使得瓦斯大量散失;开平煤田不同的构造演化过程、不同类型的构造等对煤层的非均质性产生不同程度的影响;煤层在局部变质程度、变形破坏特征等不同,进而孔-裂隙特征不同,使得局部含气性不同。

Based on the Kaiping coalfield gas geology research,using the method of hierarchical tectonic control theory,this paper systematically researched control action of different levels of tectonic activity on gas occurrence of kaiping coalfield.The results show that except coals with once coal generation process in NW part of Kaiping syncline,coals go through twice coal generation processes in other parts,because of the influences of thrust nappe structure and magmatic intrusion.Tectonic development inhomogeneity of Kaiping leads to coal the difference of gas occurrence.Due to the sealing role of reverse faults and water,there are good gas storage conditions in NW part,while gas loses too much in SE part because of the dissipation role of normal faults and water.Different tectonic evolution and tectonic types have different effects on coal heterogeneity.With different coal metamorphic grade and deformation characteristics in the local,there are different pore-fracture features,which leads to different gas-bearing properties.