DOWNHOLE FISHING MAGNET Russian patent published in 2006 - IPC E21B31/06 

FIELD: tools used during oil and gas wells to bring tool fragments, hard-alloy submagnetic drilling bit teeth and other ferromagnetic particles and objects to day surface.

SUBSTANCE: device comprises milling bit, cylindrical body with channels for well flushing formed in part of side surface and extending at an angle to fishing magnet axis. Device also has magnetic system installed on non-magnetic panel in cylindrical cavity. The magnetic system is composed of constant magnets made of rare-earth metals secured to side surfaces of ferromagnetic inserts, which form magnetic system poles. Constant magnets are arranged so that polarities thereof are oriented one towards another and the constant magnets are enclosed with C-shaped titan screens. Magnetic system pole width is not less than 1/3 of magnet width. Magnetic system and cavity are filled with filler, which provides impact resistance of the system along fishing magnet axis and prevents magnetic flux closure.

EFFECT: increased efficiency, extended service life and improved manufacturability.

3 dwg