METHOD OF IMPROVED COMBUSTIBLE GAS RECOVERY USING UNDERGROUND TWO-PHASE GAS-LIQUID VARIABLE BASED ON PHASES OF UNWORKED COAL FRACTURING IN COAL MINE Russian patent published in 2017 - IPC E21B43/26 E21F7/00 

FIELD: oil and gas industry.

SUBSTANCE: fracturable well bore and water dispensing bore are constructed in a coal seam or in a permeable layer and both bores are sealed to withstand high pressure. Fracture equipment is attached and water is forced under pressure of not more than 3 MPa into the fracturable bore of 1 well, wherein water pump is turned off after 10 minutes of fracturable well bore hydraulic fracturing, thus stopping the hydraulic fracturing. Compressed air compressor for gas-phase fracturing of fracturable well bore is turned on and when the pressure reaches 3 MPa, the compressed air compressor is turned off, thus stopping the gas-phase fracturing. These operations are repeated many times, wherein when water flows from water dispensing well bore spaced from the side wall of fracturable well bore, the hydraulic fracturing is stopped, but the gas-phase fracturing is continued. When water stops flowing from the water dispensing bore or when gas blows through the water dispensing bore, the gas-phase fracturing is stopped. Then a gas discharge pipeline network is connected to the fracturable well bore and to the water dispensing bore for combustible gas recovery.

EFFECT: increased efficiency of combustible gas recovery method.

1 dwg