CASING PIPE CENTRALIZER Russian patent published in 2006 - IPC E21B17/10 

FIELD: mining, particularly for casing pipe cementing during well construction.

SUBSTANCE: centralizer comprises body made as hollow cylinder with radial channels and connection threads at both cylinder ends, centering members formed as cylindrical rods with supports installed in radial channels and performing axial displacement, centering member retaining units and means, which transfer centering members in working position. Centralizer is also provided with shear ring composed of separate sectors fixedly connected to the rods. The sectors may cooperate with means, which transfer centering members in working position. Annular groove is created in inner body surface at radial channel level and adapted to receive shear ring sectors. Inner diameter of shear ring in its initial position is less than that of casing pipe.

EFFECT: increased operational efficiency, especially during casing of horizontal and slant well bores characterized by large zenith angles.

7 cl, 6 dwg