PERFORATOR Russian patent published in 1995 - IPC

FIELD: construction. SUBSTANCE: device consists of three sections: lower section, centralizer and upper section. Lower section consists of abrasive branch pipe which is mounted in center portion of housing perpendicularly to its axis. In center portion of abrasive branch pipe there is slotted tangential passage. Spring-loaded hard alloy checkers are arranged inside branch pipe which are directed in opposite sides. Branch pipe and checkers are fixed in housing by means of holders. Centralizer has housing with two cylindrical bores. Made opposite lower bore are lateral holes which receive spring-loaded slips. Screwed concentrically into housing is tube. Circular chambers formed between them are filled with oil. Arranged opposite upper bore is spring-loaded circular piston. Upper section consists of housing with circulating holes above which bush is mounted. Nut is screwed into housing at the top. Mounted in nut for axial displacement is rod with half-coupling and coupling at ends. EFFECT: self-filling of string with perforation fluid in the course of lowering the perforator into well, centering and fixing the perforator housing relative to casing string in course of perforation, dampening longitudinal oscillations of string, acceleration of process of creating perforation channels and increasing of their inlet sizes. 4 dwg