DEVICE FOR CONSECUTIVE CEMENTATION OF A CASING STRING Russian patent published in 2004 - IPC

FIELD: oil extracting industry. SUBSTANCE: device being mounted in the casing string with a footplate and landing saddle includes a body with circulatory apertures and an overlapping bushing connected to the body by means of shear elements and compaction. Circulatory apertures are placed above the overlapping bushing. Device has spring bushing with longitudinal recess all over the length and with a ring- shaped projection inside the inner part. Spring bushing is connected with overlapping bushing by means of shear elements in operation position in radial direction and interacts with technological bushing in operation position. Technological bushing is mounted in cylindrical recess of casing string footplate above the landing saddle. Inner diameter of technological bushing matches outer diameter of plunger with ring-shaped projection in the upper part. Plunger is mounted on the lower end of tubing string with compactions and fixing ring for interacting with inner wall of technological bushing. EFFECT: increased reliability and effectiveness, cementation process is cheaper and simpler. 2 cl, 5 dwg