Research on mechanism of tectonic stress field controlling coal permeability

Taken Qinshui basin as an example,the relationship among stress, fracture and permeability is analyzed. Firstly, The resume of paleo-tectonic stress field and its simulation with finite element method are conducted. Secondly, combined with the difference of fracture in coal seams and surrounding rocks the analysis on the feature of current crust principle stress, the distribution rules of regional fractures in coal reservoir and their controlled factors in east and southeast Qinshui basin are studied in detail. Furthermore, three controlling models of fracture & stress in Jingcheng, Lucheng and Yangquan, three coal mining districts in eastern Qinshui, have been summarized. The permeability of coal seams in entire basin is classified into three levels of the perfect, medium and poor based on above study basis.