Use of Rotary Cutting Elements in Downhole Milling

Abstract

A milling tool includes a milling arm with a rotatable cutting element positioned on the milling arm. The rotatable cutting element may be fixed longitudinally and radially relative to a rotational axis of the rotatable cutting element in the milling arm while being rotatable about the rotational axis.

What is claimed is: 
     
         1 . A downhole tool, the downhole tool comprising:
 a milling arm, and   a rotatable cutting element positioned in the milling arm and rotatable within the milling arm about a rotational axis.   
     
     
         2 . The downhole tool of  claim 1 , further comprising at least one inside cutting element positioned in the milling arm in a downhole direction of the rotatable cutting element. 
     
     
         3 . The downhole tool of  claim 2 , further comprising at least one outside cutting element positioned in the milling arm in a downhole direction of the rotatable cutting element. 
     
     
         4 . The downhole tool of  claim 3 , the milling arm having a sacrificial region between the at least one inside cutting element and the at least one outside cutting element. 
     
     
         5 . The downhole tool of  claim 1 , the rotatable cutting element having a front face including a cutting portion including an ultrahard material. 
     
     
         6 . The downhole tool of  claim 5 , less than 50% of the front face being the ultrahard material. 
     
     
         7 . The downhole tool of  claim 5 , the ultrahard material being a continuous circumferential edge of the rotatable cutting element. 
     
     
         8 . The downhole tool of  claim 5 , the rotatable cutting element have a chipbreaking feature on the front face. 
     
     
         9 . The downhole tool of  claim 1 , the rotatable cutting element being retained in a housing by one or more fasteners. 
     
     
         10 . The downhole tool of  claim 9 , wherein at least a portion of the housing is positioned within the rotatable cutting element. 
     
     
         11 . The downhole tool of  claim 1 , the rotatable cutting element being retained in a housing by at least one ring. 
     
     
         12 . A milling tool, the milling device comprising:
 a milling tool body; and   a plurality of milling arms projecting radially from the body and configured to move about the milling tool body in a cutting direction, at least one milling arm of the plurality of milling arms including,   a rotatable cutting element positioned in an arm body of the milling arm and rotatable about a rotational axis, and   at least one fixed cutting element positioned in the arm body of the milling arm.   
     
     
         13 . The milling tool of  claim 12 , the rotational axis being non-parallel to the cutting direction. 
     
     
         14 . The milling tool of  claim 12 , the rotational axis being oriented at a declination from the cutting direction between 0° and 45°. 
     
     
         15 . The milling tool of  claim 14 , the rotatable cutting element having a bevel that is complimentary to the declination. 
     
     
         16 . The milling tool of  claim 12 , the rotational axis being oriented radially outward from the cutting direction at a radial angle between 0° and 45°. 
     
     
         17 . The milling tool of  claim 16 , the rotatable cutting element having a bevel that is complimentary to the radial angle. 
     
     
         18 . The milling tool of  claim 12 , the plurality of milling arms being deployable from the body. 
     
     
         19 . A milling tool, the milling device comprising:
 a milling tool body; and   a plurality of milling arms projecting radially from the body and configured to move about the milling tool body in a cutting direction, at least one milling arm of the plurality of milling arms including,   a rotatable cutting element positioned in an arm body of the milling arm and rotatable about a rotational axis,   at least one inside fixed cutting element fixed relative to the arm body and positioned in a downhole direction of the rotatable cutting element, and   at least one outside fixed cutting element fixed relative to the arm body and positioned radially outside of the at least one inside cutting element with a sacrificial region positioned therebetween.   
     
     
         20 . The milling tool of  claim 19 , the at least one outside cutting element positioned at a radial end of the arm body.