High Stiffness Tool For Expanding A Wellbore

Abstract

A downhole tool may be used to enlarge and widen a wellbore. The downhole tool may include a reamer with a mandrel that includes a rib extending radially outward from a cylindrical body of the mandrel. The rib may define one or more grooves. A cutter block or other expandable member may be positioned adjacent the rib and may include one or more extensions that mate with the grooves. The rib and cutter block may be positioned within a slot of a housing. The housing may also include one or more grooves on a surface along the slot. The grooves along the slot and the grooves on rib may mate with extensions on opposing sides of the expandable member to define a path by which the expandable member moves between expanded and retracted positions.

What is claimed is: 
     
         1 . A reamer for widening a wellbore, comprising:
 a housing defining a plurality of slots;   a plurality of expandable members positioned within the plurality of slots; and   a mandrel within the housing, the mandrel including a plurality of ribs extending into the plurality of slots.   
     
     
         2 . The reamer of  claim 1 , the plurality of expandable members being configured to expand and retract within the plurality of slots. 
     
     
         3 . The reamer of  claim 1 , the plurality of expandable members each including at least one extension configured to mate with a corresponding groove on at least one of the housing or the plurality of ribs. 
     
     
         4 . The reamer of  claim 3 , the housing and the plurality of ribs each including at least one groove configured to mate with extensions of the plurality of expandable members. 
     
     
         5 . The reamer of  claim 4 , the plurality of expandable members being positioned to have a first side adjacent at least one groove of the housing, and a second side adjacent at least one groove of the plurality of ribs. 
     
     
         6 . The reamer of  claim 1 , the housing including a plurality of housings configured to move longitudinally relative to the mandrel. 
     
     
         7 . The reamer of  claim 1 , further comprising:
 at least one piston configured to expand the plurality of expandable members.   
     
     
         8 . The reamer of  claim 1 , further comprising:
 at least one biasing member configured to return the plurality of expandable members toward a retracted position.   
     
     
         9 . A method for widening a wellbore, comprising:
 tripping a downhole tool into a wellbore, the downhole tool including a reamer having a mandrel coupled to at least one cutter block;   providing fluid to the downhole tool through the mandrel;   using the fluid to expand the at least one cutter block relative to the mandrel, and along a path defined by a rib extending radially from the mandrel; and   rotating the downhole tool while the at least one cutter block is expanded, and thereby widening the wellbore.   
     
     
         10 . The method of  claim 9 , wherein using the fluid to expand the at least one cutter block relative to the mandrel includes using a piston to expand the at least one cutter block. 
     
     
         11 . The method of  claim 9 , wherein the path is defined by one or more mating grooves and extensions of the rib and the at least one cutter block. 
     
     
         12 . The method of  claim 11 , wherein the one or more mating grooves and extensions are oriented at an angle relative to a longitudinal axis of the mandrel. 
     
     
         13 . The method of  claim 9 , wherein the reamer includes a housing defining at least one slot, the at least one cutter block and the rib being positioned in the at least one slot. 
     
     
         14 . The method of  claim 13 , wherein the at least one cutter block includes at least one extension on a first side of the at least one cutter block and at least one extension on a second side of the at least one cutter block, the first and second sides of the at least one cutter block being opposing sides, and wherein the rib includes at least one groove mating with the at least one extension on the first side, and wherein the housing includes at least one groove mating with the at least one extension on the second side. 
     
     
         15 . The method of  claim 9 , wherein using the fluid to expand the at least one cutter block includes expanding the at least one cutter block radially and longitudinally relative to the mandrel. 
     
     
         16 . The method of  claim 15 , wherein in an expanded position, the at least one cutter block is engaged with the fin of the mandrel. 
     
     
         17 . The method of  claim 9 , wherein using the fluid to expand the at least one cutter block includes moving a housing of the reamer axially to expand the at least one cutter block. 
     
     
         18 . A reamer, comprising:
 a mandrel including a substantially cylindrical body, a flow bore, and a rib extending radially from the substantially cylindrical body;   a housing defining a substantially cylindrical shape with a slot, the rib of the mandrel being positioned in the slot;   an expandable member in the slot between the rib and a side of the slot;   a piston assembly in communication with the flow bore of the mandrel and configured to hydraulically actuate the expandable member from a retracted position to an expanded position; and   a biasing member coupled to the housing and configured to mechanically drive the expandable member from the expanded position toward the retracted position.   
     
     
         19 . The reamer of  claim 18 , the rib being integrally formed in the mandrel. 
     
     
         20 . The reamer of  claim 18 , the housing, rib, and expandable member defining a plurality of mating grooves and extensions that define a path that is angled relative to a longitudinal axis of the mandrel and along which the expandable member moves between the retracted and expanded positions.