Surface efficient gas extraction mode based on full coverage of working face

Aiming at the problems of soft and broken coal seam, low permeability, difficulty in gas extraction and low drainage efficiency in working face, a full-coverage mode for gas extraction in working face through the horizontal well group with staged fracturing roof at both ends is proposed. Taking a mine in Suxian mining area of Huaibei coalfield as an example, based on the characteristics of in-situ stress and working face distribution, combined with the analysis of gas geological conditions and coal seam mechanical properties in the area, the cross section dipole sonic logging method was used to optimize the orientation of the horizontal section of the horizontal well, and the horizontal well was determined by the Fracpro PT fracturing simulation technology. The horizontal section was away from the coal seam 7₁ arranged within 2 m of the top of the coal seam; the drainage simulation technology was used to predict the test project in the study area, the gas content and pressure of the working face have greatly reduced after 3 years of drainage, which meets the requirements of full coverage of gas drainage in working face. The extraction mode proposed in this paper provides a means for the efficient extraction of ground gas in domestic coal mines with similar conditions.