Research And Application Of High Pressure Hydraulic Slotted Drainage Technology In Pingdingshan No.10 Coal Mine

Aiming at the characteristics of difficult mining of deep coal seams,low coal seam permeability and high gas pressure.This thesis takes the tenth mine of Pingmei Group as the research object,in order to achieve the enhancement of coal seam permeability,optimize coal seam gas drainage technology,effectively prevent coal and gas outburst,and select a strong applicability,low cost,and effective anti-reflection technology to promote For the purpose of the group's use,high-pressure hydraulic slitting technology was selected to carry out research and application of anti-reflection drainage technology.The basic parameters of coal seam gas have been measured in the laboratory and on site.Then,the water flow characteristics of the high-pressure water jet are studied,and the coal breaking mechanism and the principle of pressure relief and permeability enhancement of the water jet are studied.In the field test,the effective fracture radius is determined to be 1.0m by the gas pressure reduction method.Using the borehole gas flow method,the fracture influence radius was determined to be 4.0m.After the implementation of high-pressure hydraulic slitting,the air permeability coefficient of the coal seam has been greatly improved.The air permeability coefficient at 1.5m is 2.76m~2/(MPa~2·d)increased by 145.3 times,and the area at 4.0m is1.28m~2/(MPa~2·d)increased by 67.15 times.The increase in coal permeability reduces the difficulty of extracting coal seams that are difficult to extract.At the same time,the decrease in gas pressure reduces the risk of outburst.In the numerical simulation of the influence of coal seam penetration enhancement on gas drainage,it is concluded that even if the coal seam is enhanced by negative pressure for drainage,the outburst elimination range is not continuous,and effective drainage effects cannot be achieved.After the use of high-pressure hydraulic slitting to enhance the penetration of the coal seam,the outburst elimination range is significantly increased.Compared with before the enhancement of the penetration,the better elimination effect can be achieved by using a smaller suction pressure.In the field application of high-pressure hydraulic slotted coal seam penetration enhancement drainage,it is concluded that the gas concentration of ordinary drainage holes 20days before drainage is relatively high.With the increase of the number of drainage days,the gas concentration of 4m drill holes approached about 17%.The 6m-spacing boreholes approached about 9%;the 6m-spacing split hole gas concentration was maintained at more than 80%,the7m-spacing split-hole gas concentration was maintained at about 80%,and the 8m-spacing split-hole gas concentration was maintained at about 70%.The drainage concentration has been greatly improved after the anti-reflection.Considering the efficiency of outburst elimination and economic benefits,7m is selected as the spacing of the slit holes.The use of high-pressure hydraulic slitting and penetration-enhancing drainage technology has greatly improved the effect of gas drainage,and at the same time,it has reduced the amount of engineering under the premise of meeting safe production,saved economic costs,and effectively prevented coal and gas outbursts while improving benefits.At the same time,it provides technical and theoretical guidance for other similar mines,which has great economic and social benefits.The thesis has 54 figures,19 tables and 79 references.