The Experimental Study To The Effective Scope And Restricting Factors Of Hydraulic Fracturing In Coal And Rock Seam

Hydraulic fracturing is a kind of advan ced technology which is pressure relief antireflective and effectively improves the effect of the coal seam gas extraction. Due to the implementation of the technology in the past, can’t clear judgment and control of high pressure water flow direction and scope and constraints in coal rock mass, leading to the ex ecution effect of hy draulic fracturing has great un certainty and uncontrollability, difficult to achie ve the des ired effect; even due to f ailed to understand the new stress concentration zone which high pressure water accum ulation zone create, and not tak e effective technical measures to eliminate, leave new safety hidden trouble to the m ining operation in the late period. So study the hydraulic fracturing of coal rock high pressure wate r flow scope in the coal and rock and restricting factors for reasonable guidance smooth implementation and ensure safety in production has m ore important th eoretical and practical signi ficance. Firstly, in this thesis, based on the principle of th e Transient Electromagnetic Method(TEM),the feasibility has been analyzed to detect th e flow direction and extended range of high pressure water within the coal seam during the process of hydraulic fracturing. Meanwhile, a series of experim ents have been carried out on the No.14230 working face in Yi Ma Coal Group Xin’an coal m ine and No.Ⅰ13 mining return air alleys in Huai Bei Coal Group Lin’huan coal mine. According to the conclusion of the detection and explanation to the changing disciplines of the secondary electrom agnetic field of coal seam and its roof in the experim ental area, be fore and after the hydraulic fracturing, the normal flow direction and influence scope of high pressure water along the coal seam under the action of the hydraulic fracturing ar e intuitively made clear. Secondly, taking th e coal samples from the different positions of working face an d determining moisture content of coal sa mples, the r eliability of the tr ansient electromagnetic method is also verified. Finally, using fault tree analysis m ethod, through solving the m inimum cut sets and st ructure importance, discussion has been clear about the scope of influence factors of hydraulic fracturing of the m ain mining area geological conditions and factors.