FIELD: engines and pumps.
SUBSTANCE: invention can be used in extracting methane from gassy coal seams. Prior to lowering casing string, extra pipe string is mounted with its OD exceeding OD of said casing string. Filter is mounted on lower end of the casing string and, right above it, a plug catching baffle is fitted into said baffle. Extra string is lowered into well and arranged so that plug catching baffle is located at least 2 m below lower coal seam. Jet pump unit housing is mounted on casing string lower end and furnished with channels and check valve. Housing is lowered on casing string into extra string and mounted on the plug catching baffle. Jet insert is fitted, via casing string, into aforesaid housing. Work medium is fed, via casing string, into nozzle for liquid medium to be sucked from working face. Mix of media is directed in tubular annulus and out, onto surface. Liquid medium pumped out from coal seams, gaseous medium is forced from coal seams into tubular annulus between casing and extra strings and, therefrom, onto surface.
EFFECT: higher efficiency in using in wells with liquid and gas media and solid mechanical impurities.
2 dwg
