Study On Optimization Of Gas Drainage Scheme In BaoDe Coal Mine

Aiming at the characteristics of high gas pressure,high gas content and large gas emission in the coal seam 8#of Baode coal mine,the optimization of coal mine gas extraction scheme is carried out.In order to make the research can better serve the field practice,81306 representative working face was secleted as the main research object.According to the basic parameters of the 81306 working face,we can get that the working face gas content is 6.98m3/t,the gas pressure is 1.05MPa.Take a gas emission prediction of the working face,we can get the working face gas emission is 5.44m3/t.Therefore,the 81306 working face can be drawn for the mining face.The numerical simulation of single pipe extraction was carried out by Comsol software.The variation rule of extraction radius under different drilling diameter and extraction time was studied,and the conclusion was drawn that the extraction radius had a positive correlation with drilling diameter.From the simulation results we confirms that the drainage hole diameter is 135mm,three-dimensional cross borehole spacing of the coal seam after optimization is 5m.The predrainaging optimization parameter selection method for the design of the two test drilling arrangement in 81306 working face,and the gas concentration monitoring records of each borehole,drainage quantity,the interchange drilling 100 meters average drainage quantity was 0.421m3/min hm,and the attenuation coefficient was 0.0824d-1.The average of one hundred meters parallel drilling drainage quantity is 0.335m3/min hm,and the attenuation coefficient was 0.1779d-1.After the comparison between pumping parameter and effect,we concluded that the three-dimensional cross borehole drainage effect is better.The selection method of high drilling parameters optimization is three group comparison experiments in the 81306 working face drilling field,one orifice flowmeter is installed in each drilling hole of high working area.There are totally 18 drilling drainage parameters in three groups obtained by observation of a certain period of time.By pumping the mixed volume,scalar concentration of three parameters of transverse and longitudinal comparative analysis to select the optimal high field drilling and drilling,in order to determine the optimal parameters of high drilling.Finally established the optimal scheme of gas drainage,the practice has proved that the optimization scheme is feasible.