HYDRAULIC CALIBRATOR-CENTRALISER Russian patent published in 2012 - IPC E21B17/10 

FIELD: oil-and-gas production.

SUBSTANCE: proposed device comprises casing-shaft with axial bore and jointing thread for drill tool with radial channel making the device working cavity, calibration elements fitted in grooves of limit bush for radial limited displacement. Said calibrating elements are made up of structurally independent cylindrical circular segments with blades secured thereon. Radial displacement of segments together with blades results from elastic bush expansion caused by surplus pressure in tube side.

EFFECT: simplified design, expanded operating performances, possibility to vary borehole path.

3 dwg