Importance

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Abstract

A self powered downhole tool anchor device (10) preattached to a downhole tool (T) and unitarily supported by a drill string (DS) for a single trip into a well bore, actuated by forceful engagement with the bottom or plug (P) in the well bore and attachment to a well bore casing (C). The anchor device comprises an inner mandrel (20) and lower cone (34) containing a piston (30) and fluid (F) for axially displacing an outer mandrel and piston (44) connected thereto by shear screws (46). An upper cone (20) on the outer mandrel is connected by shear pins to a slip housing (50) containing radially expandable slips (38) keyed to the lower cone (34). A self contained power supply (PS) of combustible material (M) is ignited by a firing pin (90) striking a primer igniter (I) and generates gas pressure applied to the piston 30 and fluid (F) to shear pin (46) and axially displace the outer mandrel and piston (44) upper cone (40) slip housing (50 ) slips (38) and ratchet ring (62) relative to inner mandrel (20) and cone (34). Screws (52) are then sheared off releasing upper cone (40) from slip housing (50) and allowing relative displacement therebetween to radially expand slips (38) into gripping engagement with the well bore casing (C). A mechanical firing mechanism includes a preloaded compressed spring (100) actuated hammer (98) retained against a spring housing (102) and in a cocked firing position by a shear pin (101) extending from an outer housing (96). A trigger (108) engaged by the spring housing (102) has a foot (110) which engages the bottom of or plug (P) in the well bore. Lowering of a predetermined amount of weight of the assembled unit causes pin (101) to shear and release the hammer (98) which strikes and propels the firing pin into the igniter capsule I.

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First Claim