COAL FORMATION HYDRAULIC PROCESSING METHOD Russian patent published in 2007 - IPC E21F7/00 

FIELD: mining industry, possible usage for degassing coal formations to extract methane from coal formations for its utilization in industry and for increasing safety of mining operations in mines.

SUBSTANCE: coal formation hydraulic processing method includes drilling of a well from surface with following provision of necessary facilities in it. Processing of formation is started in filtration mode, then on drop of mouth pressure of liquid down to atmospheric with following efflux of liquid from well, hydraulic impacts are created and simultaneously hydraulic energy of stream, created by force pump, is accumulated. For penetrable formations, time of effective hydro-impulse influence on formation is sufficient for accumulation of necessary hydraulic energy of working liquid stream. After completion of hydro-impulse processing of formation, working liquid is forced from hydro-accumulator into formation at high pressure, ensuring hydraulic disintegration of formation along directions of starter cracks, formed during hydro-impacts. During discharge of accumulator, at liquid pressure drop stage, pressure is focused, value of which is not less than the value of hydro-tear pressure of formation. After than forcing of working liquid into formation is stopped and formation is affected with working liquid in analogical hydro-impulse mode. These processes are repeated until planned hydro-processing areas are formed in formations around the well. During processing of formations with low penetrability, for efficient opening of cracks higher powers of working stream are required, and, therefore, more time is needed for charging hydro-accumulator. This power value is set based on physical and mechanical properties of formation. Because of that, after effective influence of hydro-impacts on formation it is exposed to hydro-static pressure during certain time. Then, modes of working liquid forced influx and efflux from the well are repeated analogically.

EFFECT: 1,5-2 times increased debit of methane, almost 3 times decreased volume of consumed water and over 3 times decreased specific energy costs of hydro-processing of a unit of formation volume.

2 cl, 3 dwg, 2 ex