CASING SHOE Russian patent published in 2023 - IPC E21B37/00 

FIELD: well construction.

SUBSTANCE: invention is intended for working out unstable sections of the shaft with zones of shedding and rock collapses. The device includes hollow body made of easily drilled material in the form of a tip with flushing holes and a cylindrical part with a connecting thread on top. The cylindrical part is equipped with blades with flat carbide teeth over the entire surface evenly at the same level as the outer surface of the blade. The body blades are made straight, equipped with carbide inserts at the working ends of the body blades in such a way that on the next blade in the direction of rotation the carbide inserts are offset relative to the previous one. The body is rigidly fixed relative to the cylindrical part, which is made undrillable with a passage channel. The helical blades of the cylindrical part are made with the lower part shifted forward in the direction of rotation relative to the upper part. At least one of the blades is made to the centre of the end surface of the body, and the length of the cylindrical part is 0.5-3.5 of the described diameter along the blades of the cylindrical part.

EFFECT: simplicity and reliability of the design, high development speed, durability of the structure, and free descent of the casing due to complete cleaning of the wellbore and the formation of an effective diameter are ensured.

1 cl, 3 dwg