Underground segmentation point hydraulic fracturing antireflection for low-permeability coal seams

The principle and process of underground segmentation point hydraulic fracturing for low-permeability coal seams were studied by means of numerical analysis and field test.Underground segmentation hydraulic fracturing is intended to change the traditional force way to make coal more force and interaction,and finally to produce the effect of fracturing.The hydraulic fracturing test at the west second mining area of Chenshan Coal Mine in northeastern China shows that when the fractured radius is 5 to 7m,the critical injection pressure is 14 MPa,and it is suitable for the hydraulic fracturing that the injection pressure is 14 to 20 MPa.The test procedure is so simple that the hydraulic fracturing can be completed within 5 min,and the average gas flow and volume fraction of gas drainage are significantly increasing after the hydraulic fracturing.