DEFLECTING DEVICE FOR OPENING CUTTING IN WELL CASING STRING Russian patent published in 2013 - IPC E21B7/08 E21B29/06 

FIELD: mining.

SUBSTANCE: device includes hollow mill-reamer fixed at drilling string, on which there hanged is a deflecting wedge by shear element that is equipped with hydraulic attachment assembly in casing string with channel for drilling mud supply coming through drilling string. Deflecting wedge has tilted surface in a form of a groove, hydraulic attachment assembly of deflecting wedge in the casing string is equipped with expansion unit and, at least, one slip that has teeth on external surface, and drilling mud supply channel represents a pipeline that connects internal cavity of mill-reamer and, hydraulic attachment assembly of deflecting wedge in the casing string. Deflecting device includes fishing sleeve with internal collar and circulation holes and nozzle orifice with central channel and seat for fault ball, all coaxially mounted inside the hollow mill-reamer. Hydraulic attachment of deflecting wedge in casing string includes cylinder sleeve connected to expansion unit of deflecting wedge, hollow rod located inside the cylinder sleeve, threaded cap connected to the bottom part of the cylinder sleeve, annular piston capable of sliding between cylinder sleeve and hollow rod, supporting bush connected to annular piston by shear screws. Hollow rod is connected to the pipeline that connects the internal cavity of mill-reamer and hydraulic attachment assembly of deflecting wedge in casing string.

EFFECT: increase of reliability of deflecting device fixing in well casing string, the structure is simplified, reduction of accident rate and cost of drilling works, provision of clean milling with smooth edges, increase of opening cutting accuracy in well casing string, reduction of vibration level, increase of cutting ability and lifetime of mill-reamer for cutting complete opening in casing string during one submerging into the well, improvement of passability of hook-up with gerotor hydraulic motor and drilling bit at the following drilling of side bore for oil extraction through cut opening in casing string wall.

5 cl, 10 dwg