ROTARY SHOE OF A CASING STRING Russian patent published in 1997 - IPC

FIELD: well drilling. SUBSTANCE: device includes a hydraulic engine. The engine has a casing. The casing is secured to the lower end of the casing string. A shaft is secured in the casing. Axial and radial bearings are used to secure the shaft. Drill pipe string is secured to the lower end of the shaft to stop the shaft against rotation in the process of grouting. Lower portion of the casing string has a joint of swing type at the length within 300 m. EFFECT: higher reliability of grouting. 1 dwg