Research Progress of Measuring Method for Influencing Radius of Borehole Gas Drainage in Coal Mine

The time-varying characteristics of the influence radius of borehole gas drainage in mines are the basis of scientific formulation of mine gas disaster control scheme and coal-bed methane development planning in coal mining areas. The measuring methods for influencing radius of borehole gas drainage, such as "pressure drop method", "tracer gas method", "gas content method" and "gas quantity method by borehole extraction", were systematically reviewed, and the application conditions, advantages and disadvantages were pointed out respectively. The research direction of the influencing radius measurement method of borehole gas drainage in coal mine in the future was prospected. The paper indicates that the synergistic response mechanism of quantifying the influencing radius of borehole gas drainage to the gas flow in coal seam, studies the rapid and accurate measurement technology of the basic parameters of coal seams gas, and establishes the space-time scale of three-dimensional coupling and multi-physical field coupling into the unified system of coal seam gas flow system will become the future research hotspot.