Drill bit and cutter element having multiple extensions

Abstract

A cutting element is disclosed having multiple cutting extensions extending from the base portion and separated by valleys. The cutting extensions of the cutting element include both crested and rounded shapes. The cutting extensions may differ in extension height, shape, extension angle, cant angle, and crest angle in other characteristics such as in material properties such as wear resistance, hardness and fracture toughness. The cutting elements have particular, but not exclusive, application in the nose portion of the cone cutters of a rolling cone bit.

1 . A cutting element for a drill bit comprising: 
 a base portion having a longitudinal axis and a cutting portion extending from said base portion;    said cutting portion comprising a non-planar foundation surface extending from said base toward said axis, a plurality of cutting extensions extending from said foundation surface, and a valley between said cutting extensions.    
     
     
         2 . The cutting element of  claim 1  wherein said plurality of cutting extensions include at least two cutting extensions having cutting surfaces that differ in at least one characteristic selected from shape, extension height, extension angle, twist angle and cant angle.  
     
     
         3 . The cutting element of  claim 1  wherein said foundation surface has a shape selected from generally frustoconical and generally dome-shaped.  
     
     
         4 . The cutting element of  claim 1  wherein said plurality of cutting extensions includes at least a first cutting extension having a first crest.  
     
     
         5 . The cutting element of  claim 4  wherein said base includes a longitudinal axis, and wherein said first crest defines a crest axis, said first cutting extension being formed such that said first crest axis does not intersect said longitudinal axis.  
     
     
         6 . The cutting element of  claim 4  wherein said base includes a cutting element axis, and wherein said cutting portion includes a first cutting extension having a first crest and first crest axis and a second cutting extension having a second crest and second crest axis, wherein said first crest axis forms a first angle of intersection with said element axis, and said second crest axis forms a second angle of intersection with said element axis that is different than said first angle of intersection.  
     
     
         7 . The cutting element of  claim 1  wherein said cutting extensions include at least three cutting extensions having cutting surfaces, and wherein at least a first of said cutting surface differs in shape from a second of said cutting surfaces.  
     
     
         8 . The cutting element of  claim 1  wherein said cutting extensions include at least a first cutting extension having a generally dome-shaped cutting surface, and a second cutting extension having a cutting surface comprising a crest.  
     
     
         9 . The cutting element of  claim 1  wherein said plurality of cutting extensions includes at least one cutting extension having a crest with first and second ends, and wherein said first end is more narrow than said second end.  
     
     
         10 . The cutting element of  claim 9  wherein said base includes a longitudinal axis, and wherein said second end of said crest is closer to said longitudinal axis than said first end.  
     
     
         11 . The cutting element of  claim 1  wherein said cutting extensions comprise materials having differing mechanical properties.  
     
     
         12 . A cutting element for a drill bit comprising: 
 a base portion and a cutting portion extending from said base portion;    said cutting portion comprising a plurality of cutting extensions extending away from said base and valleys between said cutting extensions, at least one of said cutting extensions having a crest.    
     
     
         13 . The cutting element of  claim 12  wherein said cutting portion comprises at least two cutting extensions having cutting surfaces that differ in at least one characteristic selected from shape, extension height, extension angle, cant angle and twist angle.  
     
     
         14 . The cutting element of  claim 12  wherein said plurality of cutting extensions includes at least one cutting extension having a crest that is more narrow at a first end than a second end.  
     
     
         15 . The cutting element of  claim 12  wherein said cutting portion further comprises a foundation surface adjacent said base having a shape selected from one of generally conical, and generally dome-shaped, said cutting extensions extending from said foundation surface.  
     
     
         16 . The cutting element of  claim 12  wherein a first of said cutting extensions includes a dome-shaped cutting surface and wherein a second of said cutting extensions includes a cutting surface comprising a crest.  
     
     
         17 . The cutting element of  claim 16  wherein said second cutting extension has a greater extension height than said first cutting extension.  
     
     
         18 . The cutting element of  claim 12  wherein said cutting element includes a longitudinal axis, and wherein said crest includes a crest axis, and wherein said crest axis does not intersect said longitudinal axis.  
     
     
         19 . A drill bit for drilling through earthen formations, the drill bit comprising: 
 a bit body;    at least one rolling cone cutter rotatably mounted on said bit body for rotation about a cone axis, said cone cutter including a backface, a nose portion generally opposite said backface, and a generally conical surface between said nose portion and said backface;    a plurality of cutting elements mounted in said cone cutter, at least one of said cutting elements comprising a base portion secured within said cone cutter and a cutting portion extending from said base portion, said cutting portion comprising a plurality of cutting extensions, said cutting extensions being separated by valleys.    
     
     
         20 . The drill bit of  claim 19  wherein said at least one cutting element is mounted in said cone cutter in a position selected from one of said nose portion and said generally conical surface.  
     
     
         21 . The drill bit of  claim 19  wherein said at least one cutting element further comprises a foundation surface extending from said base portion and, wherein, said plurality of cutting extensions extend from said foundation surface, said foundation surface being one of generally flat, generally frustoconical and generally dome-shaped.  
     
     
         22 . The drill bit of  claim 19  wherein at least two of said cutting extensions include cutting surfaces that differ in at least one characteristic selected from shape, extension height, extension angle, twist angle and cant angle.  
     
     
         23 . The drill bit of  claim 19  wherein at least one of said cutting extensions includes a cutting surface comprising a crest.  
     
     
         24 . The cutting element of  claim 19  wherein said at least one cutting element includes a first cutting extension having a cutting surface that is generally dome shaped and a second cutting extension having a cutting surface that includes a crest.  
     
     
         25 . The cutting element of  claim 24  wherein said second cutting extension includes an extension height that is greater than the extension height of said first cutting extension.  
     
     
         26 . The drill bit of  claim 19  wherein said at least one cutting element includes a longitudinal axis, and wherein said cutting extensions form extension angles with said longitudinal axis, and wherein said extension angles of at least two of said cutting extensions differ.  
     
     
         27 . The drill bit of  claim 19  wherein said at least one cutting element includes cutting extensions that include cutting surfaces that differ in at least one mechanical property selected from hardness, wear-resistance, and fracture toughness.  
     
     
         28 . The drill bit of  claim 22  wherein said at least one cutting element includes a longitudinal axis, and wherein said cutting element is mounted in said cone cutter such that said element axis is substantially aligned with said cone axis.  
     
     
         29 . The drill bit of  claim 28  wherein said plurality of cutting extensions includes at least a first cutting extension having a crested cutting surface and at least a second cutting element including a generally dome-shaped cutting surface.  
     
     
         30 . A drill bit for drilling through earthen formations, the drill bit comprising: 
 a bit body;    at least one rolling cone cutter rotatably mounted on said bit body for rotation about a cone axis, said cone cutter including a backface, a nose portion generally opposite said backface, and a generally conical surface between said nose portion and said backface;    at least one nose cutting element mounted in said nose portion, said nose cutting element comprising a base portion having an outer surface secured within said cone cutter, an element axis, and a cutting portion extending from said base portion, said cutting portion comprising a plurality of cutting extensions separated by valleys.    
     
     
         31 . The drill bit of  claim 30  wherein said nose cutting element is mounted in said cone with said element axis generally aligned with said cone axis.  
     
     
         32 . The drill bit of  claim 30  further comprising a plurality of said nose cutting elements retained in said cone cutter in a circumferential row that is disposed about said cone axis.