Study On Application Of Liquid CO2 Fracturing And Antireflection Technology In Baylor Mine

Liquid carbon dioxide phase change fracturing is a technique used to increase the penetration of coal seams.It has the advantages of safe and convenient use,high antireflection efficiency,and a wide range of applications.It is embodied in that it does not generate sparks,the pressure is controllable,and it is easy to store.Transportation and high security.In this paper,based on the principle of liquid phase carbon dioxide phase change cracking,combined with the blasting theory,theoretical analysis of the destructive effect of coal gas phase change induced fracture on coal rock mass and the effect of antireflection,the use of damage fracture mechanics theory to analyze the emerging crack tip The effective stress intensity factor and its variation during crack propagation,and the replacement effect of carbon dioxide on gas.Secondly,using the numerical simulation software COMSOL Multiphysics,a mechanical model of the phase change fracturing influencing radius was established.The influence radius of the phase change fracturing at 270 MPa pressure was obtained,and the effective influence radius of the phase change fracturing under the existing conditions of the Bayle coal mine was determined.It is 4,6m.The carbon dioxide phase change fracturing and bursting test under the condition of coal seam in B.ayle coal mine has achieved a good effect of increasing the permeability of the coal seam,which has increased the permeability coefficient of the coal seam by more than 26 times.After the deep hole fracturing blasting,the gas drainage effect is significant.After lifting,the drilled gas drainage volume after the carbon dioxide deep-hole cracking blasting was 4.2 to 6.9 times of the drilling flow without cracking blasting;the influence radius of the extraction was greatly increased,and it was increased from 0.8m to 4.5m.Under the conditions,the amount of drilling work can be reduced to save on the cost,of destruction;the pre-extraction rate of one month of extraction can reach 8.26%,and the gas pre-extraction rate of carbon dioxide deep-hole cracking blasting area is not 2.13%.Before the test,it is after the test.3.87 times that of the coal seam reduced the gas content and pressure in the coal seam.