Study On Enhanced Penetration Technology Of Hydraulic Fracturing In High Gas Coal Seam

Based on hydraulic fracturing and antireflection theory,this paper takes the 13-1 coal seam of Guqiao Mine as the test object,and numerical simulation is carried out by RFPA2D-Flow software.Combined with the field experiment of hydraulic fracturing,the pressure relief and pressure reduction of hydraulic fracturing is analyzed.As a result,the conclusion is that compared with pre-fracturing,the amount of pre-fractured drilled holes is reduced by 38%,the gas treatment cost is greatly reduced,and the gas recovery treatment is increased by one third and the gas treatment time is improved.One-third reduction in gas treatment costs and one-third reduction in effectiveness.The hydraulic fracturing mechanism was analyzed,the process and effect of pressure relief and pressure relief by hydraulic fracturing were introduced,the characteristics of coal seam geological structure,the mechanism of hydraulic fracturing initiation and propagation were discussed,and the solution of the stress at any point of the surrounding rock was obtained.formula.Using RFPA2D-Flow numerical simulation software to simulate,it is concluded that the crack initiation pressure of 13-1 coal seam is about 30 Mpa,and during the hydraulic fracturing implementation,the maximum water flow rate can reach 400m3/(d·m).After the hydraulic fracturing of the coal seam,the stress can be redistributed.According to the stress,the coal seam near the fracturing hole is divided into four areas,namely stress relief zone,stress concentration zone,stress transition zone and original stress zone.According to the numerical simulation,the 13-1 coal seam area is roughly divided as follows:0?28m is the stress relief area;28?40m is the stress concentration area;40?50m is the stress transition area;50m is the original stress area.Therefore,the influence radius of hydraulic fracturing is in the range of 28 to 40m.After hydraulic fracturing is completed,numerous cracks are generated inside the coal body,and a fissure network similar to the network structure is formed between the fissure and the fissure.According to the coal gas content and water content distribution map,the gas content of coal seam in the region before hydraulic fracturing is 6.7m3/t,after the hydraulic fracturing,the gas content in coal seam of this region is 3.7m3/t,and the gas content before and after fracturing is significantly reduced.Before the hydraulic fracturing,the moisture content within the 40m hole was 2.8%,and the water content after fracturing was significantly increased.From this we know that the radius of hydraulic fracturing of the 1#fracturing hole in the 1414(3)Gu Drainage Tunnel of Guqiao Mine has reached a radius of 40m.13-1 Coal seam without hydraulic fracturing has a permeability coefficient of 1.39 m2/MPa2·d.After hydraulic fracturing,the gas pressure drops to 0.61 MPa.Through a series of calculations,the coal body after hydraulic fracturing is obtained.The permeability coefficient was 13.01 m2/MPa2·d.Before and after comparison,the coefficient increased by 9.35 times.After the hydraulic fracturing of the 13-1 coal seam,the permeability coefficient has been greatly improved,and the gas drainage effect is more obvious.