SHUT-OFF VALVE FOR CASING STRING Russian patent published in 2021 - IPC E21B34/06 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to the cementing of casing strings. The casing shut-off valve contains a body, hermetically fixed in the pipe string coupling, with cementing holes for the passage of cement slurry, a locking sleeve installed inside the body above the cementing holes and fixed with shear elements. The body is made in the form of a cup, the cementing holes are made in its bottom part. The bottom part of the nozzle is equipped with a sealing gasket with holes coinciding with the cementing holes of the nozzle; a conical groove is made in the lower inner part of the nozzle with the possibility of placing a retaining ring. The locking sleeve is provided with cementing holes that do not coincide with the cementing holes in the bottom of the cup. In the upper part of the locking sleeve, a saddle is made with the possibility of seating a displacement plug. A sealing elastic ring is made in the lower part of the locking sleeve. On the outer wall of the locking sleeve, cylindrical bores are made with the possibility of installing a sealing elastic ring and a locking ring.

EFFECT: increasing the reliability and tightness of the valve.

1 cl, 4 dwg