High-gas-content coal seam punching cutting pressing and sucking integral pressure relief and antireflection gas extraction method

The invention provides a high-gas-content coal seam punching cutting pressing and sucking integral pressure relief and antireflection gas extraction method. According to the method, firstly, a floor crossing hole is constructed in a coal seam; then, drill retreating is carried out; a special drill pipe and a special drill bit for hydraulic punching are replaced in a drill hole; high-pressure water of 5 to 35MPa is introduced into the drill pipe; the drill bit is rotated and is moved to and fro, and hydraulic punching is implemented on the coal seam; and punching holes with the diameter of 0.3 to 1m are formed around the drill hole. During the drill retreating, the drill bit is moved to a coal seam section with little punching coal yield; the drill bit rotates in situ; the coal seam is cut through the high-pressure water; and flat seam cutting seam grooves are formed. The special drill pipe and the special drill bit for the hydraulic punching retreat; special hydraulic fracturing equipment is connected; and the drill hole is subjected to hydraulic fracturing according to a conventional method; and after the fracturing, the drill hole is sealed according to a conventional method, and gas extraction is carried out. The method provided by the invention breaks through the limitation of a single hydraulic measure, and realizes the integral and uniform pressure relief through punching, seam cutting, fracturing and extraction integral operation, so that the single-hole pressure relief range is improved by more than 50 percent; the single-hole gas pure flow rate is improved by more than 40 percent; the single-hole gas extraction rate is improved by more than 30 percent; and obvious economic benefits and wide application prospects are realized.