Research on Time Varying Laws of Extraction Radius for Bedding Directional 1 000 m Long Drilling

According to the occurrence characteristics of 3^# coal seam in a mine, 1 000 m drilling machine with directional long drilling technology is used for the coal seam gas drainage. The field data of gas extracting from 1 000 m drill hole were put into statistical analysis, and the attenuation parameters of gas extraction were obtained. Combined with the basic parameters of 3^# coal seam, the gas extraction radius variation can be found. Reasonable hole spacing can be concluded by analyzing and numerically simulating gas flow field among different drilling holes. Spot verification proves that the accuracy rate of extraction can reach 80%. Thus, this method is helpful to predict the effect of outburst prevention.