CASING STRING DRILLING DEVICE Russian patent published in 2023 - IPC E21B23/00 E21B19/02 

FIELD: mining industry.

SUBSTANCE: used in drilling operations, in particular for drilling wells on a casing string. Device for drilling on a casing string includes a hollow cylindrical body with a top sub having an internal thread for connection with the top power drive of the drilling rig, a sealing collar. The body is equipped with longitudinal grooves on the outside, in which rams with cutters, spring-loaded in the working position, are installed with the possibility of limited rotation on the axes and wedging in the inner wall of the casing to transmit torque when the upper power drive rotates to the right. At least two sealing collars are installed in the grooves of the top sub, which is equipped with an annular ledge in the upper part with a groove from below under the upper end of the guide funnel, placed inside the casing pipe coupling.

EFFECT: transmission of the torque both during rotation by the top power drive, and keeping the torque when drilling with a bottom-hole motor, the device is easy to manufacture and allows to effectively walk and unscrew stuck assemblies.

1 cl, 2 dwg