Blunt-nosed roller cone hybrid bit

Abstract

A roller cone for a drill bit that is configured with a number of different inserts thereon. The roller cone is also configured to have a blunted nose region where the blunted nose region is positioned radially away from a central or rotational axis of a drill bit thereby allowing for additional fixed blade cutting elements to be positioned closer to the central or rotational axis of the drill bit.

What is claimed is: 
     
         1 . A roller cone comprising:
 A body having concentrically formed around a cone axis, the body extending from an outer region to a nose region, wherein the nose region is positioned radially outward from a point along the cone axis at a distance such that the nose region has a blunted cross-sectional shape such that the blunted cross-sectional shape is configured to contact a formation with a wider surface area;   A plurality of inserts disposed on the body of the roller cone; and   A plurality of cutting elements disposed on the nose region, wherein at least one of the plurality of cutting elements has at least one cutting edge.   
     
     
         2 . The roller cone of  claim 1 , wherein the plurality of inserts on the body are crushing inserts. 
     
     
         3 . The roller cone of  claim 1 , wherein at least a second of the plurality of cutting elements having more than one cutting edge. 
     
     
         4 . The roller cone of  claim 3 , wherein the at least a second of the plurality of cutting elements has three cutting edges. 
     
     
         5 . The roller cone of  claim 3 , wherein the at least a second of the plurality of cutting elements has four or more cutting edges. 
     
     
         6 . The roller cone of  claim 1 , wherein the at least one cutting edge is a continuous cutting edge. 
     
     
         7 . The roller cone of  claim 1 , wherein the blunted cross-sectional shape is selected from a group consisting of concave, convex, flat, and variable spline. 
     
     
         8 . A roller cone for a drill bit comprising:
 A body concentrically formed around a cone axis, the body extending from an outer region to a nose region, wherein the nose region is positioned radially outward from a point along the cone axis at a distance such that the nose region has a blunted cross-sectional shape such that the blunted cross-sectional shape is configured to contact a formation with a wide surface area;   A plurality of inserts disposed on the body of the roller cone; and   A plurality of cutting elements disposed on the nose region, wherein the plurality of cutting elements comprises at least one cutting element with a continuous cutting edge and at least a second cutting element with at least one cutting edge.   
     
     
         9 . The roller cone of  claim 8 , further comprising at least a third cutting element disposed on the nose region, wherein the at least a third cutting element has more than one cutting edge. 
     
     
         10 . A drill bit comprising:
 a bit body having a rotational axis;   a roller cone supported by the bit body, the roller cone including:
 a nose region, the nose region being positioned radially back from the rotational axis at a distance thereby forming a wide surface area and a blunted design, and wherein the nose region further comprises a plurality of cutting elements arranged thereon, at least one of the plurality of cutting elements has at least one cutting edge; and 
   a first fixed blade fixed relative to the bit body with fixed blade cutting elements affixed thereto radially overlapping at least the first central region.   
     
     
         11 . The drill bit of  claim 10 , further comprising at least a second roller cone, the at least second roller cone further being supported by the bit body, the at least second roller cone including:
 a second cone nose region, the second cone nose region being positioned radially back from the rotational axis thereby forming a wide surface area and a blunted design, and wherein the second cone nose region further comprises at least one cutting element arranged thereon, at least one cutting element having at least one cutting edge.   
     
     
         12 . The drill bit of  claim 10 , wherein the roller cone further comprises a plurality of inserts on a roller cone body. 
     
     
         13 . The drill bit of  claim 12 , wherein the plurality of inserts are crushing inserts. 
     
     
         14 . The drill bit of  claim 11 , wherein the at least second roller cone comprises a plurality of second cone inserts on a second roller cone body. 
     
     
         15 . The drill bit of  claim 14 , wherein the plurality of second cone inserts are crushing inserts. 
     
     
         16 . The drill bit of  claim 10 , wherein at least a second of the plurality of cutting elements has more than one cutting edge. 
     
     
         17 . The drill bit of  claim 16 , wherein the at least a second of the plurality of cutting elements has three cutting edges. 
     
     
         18 . The drill bit of  claim 16 , wherein the at least a second of the plurality of cutting elements has four or more cutting edges. 
     
     
         19 . The drill bit of  claim 10 , wherein the at least one cutting edge is a continuous cutting edge. 
     
     
         20 . The drill bit of  claim 11 , wherein the at least one cutting element has a continuous cutting edge. 
     
     
         21 . The drill bit of  claim 11 , further comprising at least two cutting elements. 
     
     
         22 . The roller cone of  claim 1 , wherein the distance is at least 10% of a drill bit body diameter. 
     
     
         23 . The drill bit of  claim 10 , wherein the distance is at least 10% of a diameter of the bit body.