Method for locally extracting gas of soft coal seams

The invention discloses a method for locally extracting gas of soft coal seams. The method includes drilling bedding holes in coal roadways by the aid of drill rigs, hollow drill rods and gate-type drill bits until the depths of the bedding holes reach set depths, then enabling the drill rigs, the hollow drill rods and the gate-type drill bits to stall, and discharging slag by the aid of compressed air under the pressure of 0.8-1.2MPa in drilling procedures; detaching connecting components between the drill rigs and the hollow drill rods, and arranging fracturing screen pipes in the hollow drill rods; withdrawing the hollow drill rods and forming hole sealing sections at orifices of the bedding holes; connecting the fracturing screen pipes with fracturing pump units by pipe fittings; connecting the hollow drill rods with the gate-type drill bits, drilling a next bedding hole and keeping the distance between the centers of every two adjacent bedding holes within the range of 5-10 meters; drilling all bedding holes in set regions and connecting all the fracturing screen pipes with the fracturing pump units; performing hydraulic fracturing; detaching the fracturing pump units, connecting the coal roadways with downhole gas extracting systems for coal mines and extracting the gas of the coal seams until leakage of the gas of the coal seams conforms to safety coal extraction standards. The method has the advantages of few drilled holes, high extraction efficiency and coal extraction efficiency and safety in coal extraction work.