GUN PERFORATOR Russian patent published in 2009 - IPC E21B43/11 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil-producing industry, specifically to well site construction and servicing, and can be used for perforation tunnelling in casing pipe. Gun perforator attached to pipe string from above, contains the body designed as a notched wedge, piston cylinder mounted in the body so that the piston underside cavity is connected to inside borehole cavity, while the piston upperside cavity is connected to collection chamber of the case arranged above the cylinder and made of upper and lower parts, concentrically connected with tight axial restricted mutual motion. Besides gun perforator accommodates radially notched support supplied with wedge capture and made of downright conical parallel portion and stop block, cutting tools movable towards wedge notches and support radial notches, anchor latch assembly arranged on the support parallel portion, axially movable and comprising rigid positioner with guide pin and cutter arms spring-loaded inwards interacting with support conical portion while activated. Upper part of the chamber is connected from above to inside borehole cavity, while lower part thereof is connected to the piston. External surface of support parallel portion contains the grooves interacting with the guide pin and consisting of axial short-length and long-length parts connected through shaped channel so that uncontrolled reciprocation of the anchor latch assembly relative to the support cause the guide pin to be settled within short-length part in transport position, while its controlled raising of smaller height of shaped groove segment connected directly to long-length part activates the guide pin to move and to be settled within long-length part in working position. Furthermore piston internal space is connected with inside borehole cavity through lower inlet valve.

EFFECT: provided reliability ensured by unauthorised activation protection; herewith the device does not require pumping unit at wellhead and great fluid to fill a hole annulus or tube side of pipe string.

2 cl, 4 dwg