METHOD FOR EXTRACTION OF METHANE FROM TECHNOGENIC COLLECTORS OF WORKED-OUT FIELDS OF OPERATING OR SHUT DOWN COAL MINES

摘要

A method for extraction of methane from technogenic collectors of worked-out fields of operating or shut down coal mines includes determination of intervals of rock unloading over the worked out coal seams, with determination of remaining methane reserve density in gas rocks within those intervals, drilling surface wells there and extraction of methane. To increase characteristics of flow rate and gas recovery of surface wells due to increase of dimensions of zone of methane inflow, the interval of rock unloading is determined with account of coefficient that takes into account the effect of the level of coal metamorphism on dimensions of arch of rock unloading, extraction power of worked out coal seam and average value of limiting tensile deformations of gas rocks. And remaining methane reserve density in gas rock is determined with account of distance by normal from the ceiling of the worked-out coal seam to the middle of thickness of gas rock, thickness of gas rock and natural gas content for rock before mining works.