UNDERGROUND COAL GASIFICATION TECHNIQUE Russian patent published in 2012 - IPC E21B43/295 

FIELD: underground coal gasification.

SUBSTANCE: invention belongs to the mining engineering and may be used for the underground coal gasification (UCG). The technique lies in drilling of development wells of the underground gas generator, implementation of a technological UCG process and minimization of the environmental impact on the massif mass. The direction of the drilled well is oriented at its lower bench, while vertical water wells and initial spots of directionally drilled well are located beyond the active displacement zone. The distance between the blasting and pressure relief well shall be greater than the roof fragmentation step. Ignition of the coal formation is carried out in the vertical well, what is followed by a monitoring of its connectivity with the cross sectional horizontal and boundary pressure relief wells. The monitoring of coal formation outgasing is carried out between every pair of blasting and pressure relief well; such outgasing is equaled along the underground gas generator. Gasification plot is preliminary dried to the level of 20-25 m over the inflammation horizon and keep up pressure in the underground gas generator, which should be lower, than the underground water pressure. Upon the cessation of the underground gas generator exploitation the blasting wells are injected with nitrogen for a final fire face extinguishment.

EFFECT: optimum implementation of UCG technique within the whole cycle.

15 cl, 2 dwg