DOWNHOLE CALIBRATOR Russian patent published in 2020 - IPC E21B17/10 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry, namely to devices for calibrating a well shaft before entering a cut-out window of a side hole of a drilling assembly by a wedge-deflector installed in the main shaft. Well calibrator includes guiding and centring units made with possibility of connection to the drill string and consisting of hollow housing with cutting teeth of increased strength. Body is connected to the drill string at an angle of entry into the cut out window of the casing string for the offshoot. Guiding unit is made in the form of a cylinder with an external thread having a pitch equal to or greater than the thickness of the wall of the casing string, and longitudinal teeth on the thread, and with an end equipped with a spiral recess with a longitudinal edge directed towards the rotation of the bottomhole motor. Centring assembly is installed between the downhole motor and the guiding unit and is made in the form of a cylinder with diameter corresponding to the diameter of the drilling tool for construction of an additional bore with input and output chamfers along the edges and cutting edges from the outside along the perimeter.

EFFECT: invention makes it possible to enter into the cut out window of the casing string under the side bore and prepare it for passage of the drilling assembly.

3 cl, 1 dwg