METHOD OF GAS PRODUCTION BY ALTERNATE USE OF MULTI-STAGE CRACKING OF COAL MASSIF DURING COMBUSTION WITH FORMATION OF SHOCK WAVE AND HEAT-CARRIER INJECTION Russian patent published in 2020 - IPC E21B43/26 E21F7/00 

FIELD: mining; gas industry.

SUBSTANCE: present invention provides a method of increasing gas production through alternate use of multi-stage cracking of coal massif during combustion with formation of shock wave and heat-carrier injection, in which a large amount of N₂ or CO₂ is pumped into a borehole using a discharge pipe for injecting heat carrier and gas, a high pressure gas cylinder and a pressure reducing valve, after which a certain amount of methane and dry air is injected into the combustion chamber with high temperature and high pressure using a high-pressure gas cylinder and a pressure reducing valve, that after blending and combustion a shock wave is formed, and when pressure at high temperature and high pressure of combustion chamber reaches 30 MPa, then electromagnetic valve is automatically started and instantly there is shock wave of high temperature and high pressure, aimed at pushing of piston for compression of N₂ or CO₂, so that in coal massifs on the well periphery a large number of cracks is formed. High-temperature steam is pumped into boreholes by means of a discharge pipe for injection of heat carrier and gas for stimulation of desorption of coal massifs. Cracking during combustion with formation of shock wave and injection of heat carrier are repeated, wherein cracking and injection of heat carrier are performed in turns to form a larger number of cracks in coal massifs on periphery of boreholes, as well as to stimulate desorption of gas flow and further increase of high-efficiency gas production in boreholes.

EFFECT: disclosed is a method of increasing gas production.

6 cl, 1 dwg