Study On FSF Integrated Gas Control Technology And Application In Xuehu Coal Mine

Coal and gas outburst accident has always been one of the important hidden dangers restricting coal mine safety production.How to effectively prevent coal and gas outburst is an urgent problem to be solved.Xuehu Coal Mine is a high gas outburst mine,which has high gas pressure,high gas content and poor permeability coefficient.In the process of gas control,there are a series of problems,such as large amount of treatment and drainage works,long drainage time,low drainage effect and so on.How to solve these problems has been an urgent need for coal mine research.Therefore,based on the existing hydraulic measures,the project plans to carry out the research on the composite hydraulic comprehensive gas prevention and control technology,specifically from the four aspects of field investigation,theoretical research,test and field test to carry out the research on the integrated gas prevention and control technology and application of flushing-soltting-fracturing(FSF)in Xuehu Coal Mine.The main research contents are as follows:(1)The regional structure and evolution law,gas occurrence structure control characteristics of Xuehu Coal Mine are systematically studied,gas geological units are analyzed and divided,and gas geological rules are revealed in Xuehu well field.Gas content,gas emission prediction,structural coal recognition and coal seam gas resource calculation are carried out.The gas content of coal seam 2 in different gas geological units is predicted by mathematical model.Among them,the gas content gradient is 2.81 m~3/t/100m,which provides the basic basis for gas control methods.(2)By using RFPA software to carry out numerical simulation and field investigation,the best coal expansion amount of gas drainage borehole hydraulic expansion in coal seam 2 of Xuehu Coal Mine is determined.The hydraulic fracturing effect simulation after hydraulic reaming is carried out:the larger the diameter of the hole expansion,the better the hydraulic fracturing effect is.When the hole diameter is larger than 0.4m,the hydraulic fracturing effect of the drilling hole does not change significantly;when the diameter of the hole expansion is 0.4m,the fracturing pressure of the hydraulic fracturing is about 15MPa,and the second and third-stage cracks will be further produced with the further increase of the water injection pressure.(3)The hydraulic fracturing effect of the drilling after the directional hydraulic cutting is simulated by RFPA.The influence range of hydraulic fracturing after cutting is larger than that of conventional drilling.The fracturing pressure after cutting is less than 15MPa.The influence range of pore pressure is distributed in ellipsoidal annular distribution by directional cutting.The longer the length of the cut,the wider the influence range is,and the directional cutting can be determined Fracturing with water injection.(4)The slag removal and safety guarantee technology in the process of"flushing-soltting-fracturing"integration process are studied,and a set of regional outburst prevention technology system is formed which is suitable for the drilling of the second coal seam in Xuehu Coal Mine.After the application of the integrated technology of"flushing cutting pressure",the gas extraction concentration was significantly increased,and the average extraction concentration of the test borehole was 1.85 times of that of the ordinary drilling.The average extraction purity was significantly improved,the average daily average extraction purity of the test drilling was 0.009m~3/min,while the average daily average extraction purity of ordinary drilling was 0.0042 m~3/min;the average extraction purity of the test drilling was 2.12times of that of the ordinary drilling.This paper has 31 Figures,23 Tables and 64 references.