Methods of forming earth-boring tools including replaceable cutting structures

Abstract

Methods of forming an earth-boring tool may involve attaching one or more cutting elements to a replaceable cutting structure and positioning the replaceable cutting structure proximate a region of a body of an earth-boring tool that is susceptible to at least one of localized wear and localized impact damage. The replaceable cutting structure may be secured to the body. Methods of repairing an earth-boring tool may involve bringing a replaceable cutting structure proximate at least one portion of a body of an earth-boring tool exhibiting at least one of localized wear and localized impact damage. The replaceable cutting structure may be attached to the earth-boring tool at the at least one portion.

1 . A method of forming an earth-boring tool, comprising:
 positioning an annular attachment member of a replaceable cutting structure in a mold configured to form a body of an earth-boring tool at a portion of the mold configured to form a region of the body that is susceptible to localized wear, the replaceable cutting structure comprising a cutting portion located to engage an earth formation; and   forming the body around the attachment member of the replaceable cutting structure within the mold, the replaceable cutting structure being located on each blade of a plurality of blades at least within a shoulder region a face of the body, wherein an exposed surface of the replaceable cutting structure is at least substantially flush with exposed surfaces of the body adjacent to the replaceable cutting structure, and wherein the attachment member extends contiguously around a circumference of the face of the body at least within the shoulder region.   
     
     
         2 . The method of  claim 1 , wherein forming the body around the replaceable cutting structure within the mold comprises one of casting the body around the replaceable cutting structure within the mold and sintering the body around the replaceable cutting structure within the mold. 
     
     
         3 . The method of  claim 1 , wherein forming the body around the attachment member of the replaceable cutting structure within the mold comprises forming an internal plenum extending at least partially through the body and forming an outlet in fluid communication with the internal plenum to extend from the internal plenum to the replaceable cutting structure. 
     
     
         4 . The method of  claim 3 , wherein the annular attachment member comprises a channel extending at least partially through the annular attachment member and wherein positioning the annular attachment member in the mold comprises positioning the channel to align with a location of formation of the outlet. 
     
     
         5 . The method of  claim 1 , further comprising attaching a plurality of cutting elements to the annular attachment member to form the replaceable cutting structure before positioning the annular attachment member within the mold. 
     
     
         6 . The method of  claim 5 , wherein attaching the plurality of cutting elements to the annular attachment member comprises attaching a first cutting element of the plurality to the annular attachment member at a first position relative to a central axis of the annular attachment member and a second cutting element of the plurality to the annular attachment member at a second position relatively closer to the central axis of the annular attachment member. 
     
     
         7 . The method of  claim 1 , wherein forming the body around the attachment member of the replaceable cutting structure within the mold comprises casting the body around the attachment member of the replaceable cutting structure within the mold. 
     
     
         8 . The method of  claim 1 , wherein forming the body around the attachment member of the replaceable cutting structure within the mold comprises capturing the attachment member in the body due to shrinkage of the body during a densification process. 
     
     
         9 . The method of  claim 1 , wherein positioning the annular attachment member of the replaceable cutting structure in the mold comprising positioning the annular attachment member, the annular attachment member comprising planar surfaces at right angles to one another at inner and lower surfaces of the attachment member, in the mold. 
     
     
         10 . The method of  claim 1 , wherein forming the body around the attachment member of the replaceable cutting structure within the mold comprises forming at least one cutting element accommodation recess in the body, the at least one cutting element accommodation recess having a cutting element secured to the replaceable cutting structure disposed at least partially therein. 
     
     
         11 . The method of  claim 1 , wherein positioning the annular attachment member of the replaceable cutting structure in the mold comprises positioning the annular attachment member of the replaceable cutting structure, a size of the replaceable cutting structure corresponding to a predicted region of localized wear, in the mold. 
     
     
         12 . The method of  claim 1 , wherein positioning the annular attachment member of the replaceable cutting structure in the mold comprises positioning the annular attachment member, the annular attachment member comprising a cermet material, in the mold. 
     
     
         13 . The method of  claim 1 , further comprising disposing a hardfacing material on an exterior portion of the annular attachment member. 
     
     
         14 . The method of  claim 1 , further comprising:
 retrieving the earth-boring tool from a wellbore after using the earth-boring tool, the earth-boring tool exhibiting at least one of localized wear and localized impact damage and removing the replaceable cutting structure;   bringing another replaceable cutting structure proximate each blade of a plurality of blades at least within a shoulder region of a face of a body of the earth boring tool exhibiting at least one of localized wear and localized impact damage, the other replaceable cutting structure comprising an annular attachment member exhibiting a geometry cooperative with the body and each blade, and a cutting portion located to engage an earth formation, wherein an exposed surface of the attachment member is at least substantially flush with exposed surfaces of the body adjacent to the attachment member, and wherein the attachment member extends contiguously around a circumference of the face of the body at least within the shoulder region; and   attaching the other replaceable cutting structure to each blade.   
     
     
         15 . The method of  claim 14 , further comprising machining the at least one portion of the body of the earth-boring tool to a geometry predefined to cooperate with the geometry of the attachment member. 
     
     
         16 . The method of  claim 14 , further comprising positioning the replaceable cutting structure over an outlet in fluid communication with an internal plenum of the body. 
     
     
         17 . The method of  claim 16 , wherein the annular attachment member comprises a channel extending at least partially through the annular attachment member and wherein positioning the replaceable cutting structure over the outlet in fluid communication with the internal plenum of the body comprises aligning the channel with the outlet. 
     
     
         18 . The method of  claim 14 , further comprising attaching a plurality of cutting elements to the annular attachment member to form the replaceable cutting structure. 
     
     
         19 . The method of  claim 18 , wherein attaching the plurality of cutting elements to the annular attachment member comprises attaching a first cutting element of the plurality to the annular attachment member at a first position relative to a central axis of the annular attachment member and a second cutting element of the plurality to the annular attachment member at a second position relatively closer to the central axis of the annular attachment member.