METHOD OF METHANE EXTRACTION FROM COAL SEAM Russian patent published in 2015 - IPC E21B43/25 E21B28/00 

FIELD: mining.

SUBSTANCE: according to the method acoustic, electric, mechanical and hydrodynamic compressing and pulling stresses are formed by acting by periodic short impulses by means of explosion of a calibrated conductor placed in a working interval of a well. This energy of explosion is brought to the coal seam. In the well the slot-hole perforation is created which is oriented in the directions of main stresses in the coal seam. An additional slot-hole perforation is formed in permeable rocks containing the coal seam. The direction of additional slot-hole perforation is oriented in the directions of the main stresses of the rocks containing the coal seam. It strengthens acoustic and hydrodynamic cavitation of gas bubbles emitted from coal, fractures, microfractures, pores, micropores, capillaries, microcapillaries of the coal seam. Fractures and microfractures are also formed in the permeable rocks containing the coal seam. It favors to development of mesh of abnormal microfracturing in the coal seam and additional fractures and microfractures in the permeable rocks containing the coal seam. In general all factors provide the maximum desorption and diffusion of methane.

EFFECT: increase of production of coal methane, reduction of energy consumption, improvement of safety and environmental friendliness of the process.

5 dwg