HYDROPERFORATOR Russian patent published in 1995 - IPC

FIELD: repair and insulation works in wells. SUBSTANCE: hydroperforator has two interconnected sections. Upper section has hollow body with notched side walls, with notches being made in the form of holders for receiving hard-alloy inserts formed as generating and reversed cones. Side surface of generating cone is further provided with helical grooves. Inserts are provided with channels. Split rings are positioned within holders in spaced relation with respect to inserts. Retainer has body with axial channel and through channels extending in four planes. Spring-loaded stems and plugs are positioned within through openings. Cover is mounted in the vicinity of bottom portion of axial channel and spring-loaded blind piston is mounted adjacent to upper portion of axial channel. Chamber defined between cover and piston is filled with oil. EFFECT: reliable centering and retaining of body in casing string, increased tightness and service life of members of oil-filled retainer in abrasive, corrosive and high-temperature medium, elimination of enhanced abrasive wear by baffled streams of liquid flowing through perforations, intensified process of making deep perforated channels with increased input opening section in casing string. 4 dwg