Study on effective gas drainage area based on anisotropic coal seam

The paper is devoted to explore parameters that affect the effective drainage area around the hydraulic slotting.The coupling effect of the coal strain field and the gas seepage field in gas drainage is studied based on the anisotropy of coal.The influences of different vertical geostress, initial gas pressure, and initial permeability on the effective drainage area of hydraulic slotting are also analyzed.The results show that higher vertical ground stress is associated with lower coal permeability, which leads to the gradual reduction of effective drainage area.The larger the initial gas pressure is, the more difficulty it is to reduce the gas pressure around the borehole to 0.74 MPa or less, with the effective drainage area being gradually reduced.The larger the initial permeability, the higher the gas flow velocity of the coal body fissure, and the effective drainage area gradually increases under the same drainage negative pressure.The simulation results of anisotropic coal body are basically consistent with the field test results, which proves that the effective drainage radius of the anisotropic coal seam vertical bedding direction is a reasonable index of the field hole.