The invention provides an entitative
coal seam gas drainage drilling hole double-
pipe drainage method, which is particularly applicable to a
coal mine underground entitative
coal seam long-distance and large-aperture gas drainage drilling hole. A gas drainage
pipe is sent into the drainage drilling hole to the hole bottom, a flexible sleeve
pipe with the
diameter being twice the
diameter of the gas drainage pipe is sheathed at the back part of the gas drainage pipe, a 3-4m pattern hole is formed at the front end of the flexible sleeve pipe, a first
polyurethane double-material hole sealing bag and a second
polyurethane double-material hole sealing bag are respectively and fixedly arranged in positions with distances being 4 to 5m and 22 to 23m from the front end of the flexible sleeve pipe by
adhesive tapes, and the flexible sleeve pipe is sent into the drainage drilling hole after the hole sealing bags are extruded so that the second
polyurethane double-material hole sealing bag is 2 to 3m away from the hole opening of the drilling hole; after the polyurethane is cured,
cement mortar is filled between the two polyurethane hole sealing sections; and after the
cement mortar is cured, the flexible sleeve pipe is connected into a gas drainage net for gas drainage. The method has the advantages that the structure is simple, the operation is convenient, and the problem of gas
drainage flow rate reduction can be effectively solved.