NONDRILLED SLEEVE FOR STAGE CEMENTING OF CASING STRING Russian patent published in 2001 - IPC

FIELD: well drilling, particularly, devices for well cementing. SUBSTANCE: sleeve has a hollow cylindrical body, carrying unit with washing unit, control unit with lower sleeve seat and sealing members. The hollow cylindrical body has washout holes, circular recess on external surface, axial grooves in lower part of internal surface and bypass holes. Carrying unit has bore secured by sleeve with casing pipe of the first stage, washout holes. Said holes are located coaxially relative to body washout holes. Unit also has conical recess for seating of split retaining ring. Washout unit has bushing fastened to the body by shear screws and made in its lower part with longitudinal protrusions entering body mating grooves with washout holes located coaxial to the body washout holes. Control unit has plug with reinforced metal base and closing body washout holes, and wire winding located in body circular recess. Lower sleeve seat of control unit overlaps bore washout holes and has conical projections in internal surface which correspond to an angle of inclination of flexible members of plug for cementing the lower stage. Upper sleeve seat is secured to bore for motion and opening of bore holes and transmission of pressure through said holes to circular space. The latter is formed by bushing, body, bore and body lock with bore. Body with bushing and bushing with bore are sealed with several sealing members. EFFECT: higher quality of cementing of lower cementing stage. 5 dwg