METHOD OF HYDRAULIC FRACTURING OF COAL SEAM Russian patent published in 2003 - IPC

FIELD: mining, particularly, hydraulic fracturing of coal seams to provide zones with high draining ability for coal methane withdrawal. SUBSTANCE: method includes drilling in coal seam of one central hole and several periphery holes uniformly spaced from central one. Mass of coal seam is ruptured by area with help of its hydraulic fracturing with water, with closed periphery holes. Static pressure is measured and after its stabilization, air under high pressure is injected into central hole and water injection air injection cycle is repeated multiply with constant measurement of pressure in all holes. After stabilization of holes pressure, hydrodynamic action on coal seam is discontinued, and water is injected through periphery holes. Central hole is opened to atmosphere with some time delay. Then, water injection is alternated with air injection, and amount of coal carried out from central hole is measured, which is equivalent to volume of artificial reservoir produced in coal seam. EFFECT: higher efficiency of coal seam degassing. 1 dwg