MILL-REAMER FOR CUTTING SIDE "WINDOW" IN CASING PIPE OF WELL Russian patent published in 2010 - IPC E21B29/06 E21B7/08 

FIELD: oil and gas production.

SUBSTANCE: facility consists of hollow case with axial through outlet channel and of metal destructing elements. The case is single and encloses a kick-off and heading mill-reamers. External diametre of the kick-off mill is smaller, than that one of the heading mill. Outside a lower part of the kick-off mill narrows to an end in form of a straight truncated cone or ellipsoid. Threaded orifices for securing a wedge-deflector are made on this lower part. Diametre of the through channel coming out the lower end of the kick-off mill is as big, as thickness of a cut-out part of the column. At output this channel is made in form of a reverse truncated cone with metal destructing elements applied on its surface. A grip unit is secured to an axially rotating bushing installed inside the case above its lower end. The fixing element of the grip unit is made out of flexible-elastic material with preliminary specified arresting properties. This retains completely cut out metal tape, when mill is lifted from the well. Inclined through flushing channels coming outside are made in the body of the kick-off mill case. Lengthwise channels are made between facing surfaces of the grip unit bushing and the case.

EFFECT: expanded process functionality, raised operational reliability.

4 cl, 2 dwg