Research On Coalbed Methane Extraction Technology Of NO.3 Coal Seam In Wuyang Coal Mine

With the deepening of the mine mining depth and mining intensity increasing, coal seam gas emission is bigger and bigger, which is a serious influence on coal mine safety production.The gas disaster occupy a large proportion in coal mine safety accident, especially for high-gas coal mine,the problem is more serious.On the one hand, the gas extraction has played an important effect on gas disaster prevention and control, on the other hand, the gas as a clean and efficient energy has great economic benefits.Rational and efficient extracting coal seam gas is significant to safe and efficient coal mining.In this paper,according to the relevant theory of gas migration law in coal seam and during extraction the gas's transport law of the coal seam surrounding the borehole.On the basis of gas flow equation,coal mass deformation equation,permeability injury equation and rheological behavior equation and then establish a solid-gas coupled numerical model.Combine with the actual conditions of 7803 working face,Wuyang Coal Mine, COMSOL software can be used for numerical simulation calculation.Through numerical simulation calculation in different drainage arrangement and different extraction parameters,then verified by a final engineering field test. Ultimately determine hole groups extraction is the best extraction method for Wuyang Coal Mine, reasonable borehole spacing is 2.5m,the optimum extraction time was 60 days, and the optimum extraction negative is 15kPa.From gas drainage test on face 7803 in 3# coal seam, monitoring and record the gas concentration changes in 7803 roadway and the upper corner.By comparing the data before and after extraction, we found that the return airway and upper-corner concentration were significantly lower, return airway gas concentration was 0.53%at the highest, gas treatment effect is obvious.