Research and application of directional hydraulic fracturing through layers for preventing and controlling coal and gas outbursts
Fan Hongbin
Abstract：In coal seams with high gas,high crustal stress,high outburst risk,and low permeability,implementing regional pressure relief and permeability enhancement to eliminate outbursts has become one of the important measures to achieve sustainable development of coal mines.Based on the problems encountered in the application of pressure relief,permeability enhancement,and outburst elimination tech-nology,a combination of theoretical research,RFPA2D—Flow numerical simulation,and field testing was used to study the initiation mecha-nism and propagation law of directional hydraulic fracturing fractures through layers.Research has shown that the initiation of hydraulic fracturing through layers depends on factors such as the magnitude of axial and radial horizontal stresses in fracturing hole,the physical and mechanical properties of coal rock,and the weakest layer inside.Single-hole hydraulic fracturing can achieve a pressure relief radius of 7-8 meters,but there is a stress concentration zone on the outer side,which is not conducive to regional pressure relief and permeability enhancement.Multi-hole directional hydraulic fracturing forms a nearly cylindrical compression fracture zone,and a through crack surface is generated in the centerline direction of the fracturing hole and directional hole,effectively eliminating the phenomenon of stress concen-tration in non-directional hydraulic fracturing.The results showed that the gas content in coal seam of No.2238 auxiliary roadway test area in a certain mine decreased by about 42.3％,effectively reducing the risk of coal and gas outbursts.
Keywords：hydraulic fracturingcoal and gas outburstdrilling through layerswater injection pressure
Publication Date：2025-10-30
Online Publishing Date：2025-11-27(First online date of this platform, not the publication date of the document)
Pages：9( 115-123 )