Reamer with balanced cutting structures for use in a wellbore

Abstract

An earth boring drill bit comprising cones, each cone having rows of inserts, where the inserts are in the form of a pyramid with four sides. The insert includes ridges at the juncture of each adjacent side. The ridges extend to the top of the insert and meet at a crest. Oppositely disposed ridges on the insert lie substantially in the same plane, thereby forming two planes intersecting on the crest. The two planes are substantially perpendicular. The inserts are arranged on the cone such that one plane is substantially parallel with the insert row, and the other is substantially parallel with the cone axis.

1 . An earth boring bit comprising:
 a bit body:   a cutter cone rotatingly mounted on the bit body;   a row of inserts arranged on the cutter cone along a ringlike path;   a first ridge on the upper surface of each insert and oriented generally parallel with the cone axis; and   a second ridge on the upper surface of each insert oriented generally parallel with the path and intersecting the first ridge.   
   
   
       2 . The earth boring bit of  claim 1 , further comprising a crest on upper surface of each insert defined where the first and second ridges intersect on the insert and a base on the end of the insert that attaches to the cutter cone, wherein the ridges extend from the crest to the base. 
   
   
       3 . The earth boring bit of  claim 2  wherein the crest is proximate the midpoints of the first and second ridges. 
   
   
       4 . The earth boring bit of  claim 2 , wherein planar faces are formed on each insert surface in the area between where the first and second ridges extend from the crest to the base. 
   
   
       5 . The earth boring bit of  claim 4  wherein the ridge is defined by the border of adjacent faces. 
   
   
       6 . The earth boring bit of  claim 5 , wherein the ridge is an angle defined by the intersection of adjacent faces. 
   
   
       7 . The earth boring bit of  claim 5 , wherein the ridge is a curved section defined by the intersection of adjacent faces. 
   
   
       8 . The earth boring bit of  claim 1 , wherein the first and second ridges have a substantially equal length. 
   
   
       9 . The earth boring bit of  claim 1 , wherein the first and second ridges have an unequal length. 
   
   
       10 . An earth boring bit comprising:
 a bit body;   roller cones rotatingly attached to the bit body; and   a row of inserts arranged in a substantially circular path on each roller cone outer surface;   each insert having;
 a base on the end where it attaches to the roller cone cutter, 
 a first ridge on its upper surface extending along a line generally parallel with the cone axis, 
 a second ridge on its upper surface extending along a line generally parallel with the circular path and intersecting the first ridge, and 
 faces on the upper surface provided between the first and second ridges extending from where the first and second ridges intersect to the base, the faces joining at an angle, so that material displaced during boring operations is directed by the angled faces to open spaces on the bit and not trapped between inserts. 
   
   
   
       11 . The earth boring bit of  claim 10 , wherein the first and second ridges intersect proximate to their respective midpoints. 
   
   
       12 . The earth boring bit of  claim 10 , wherein the first and second ridges have substantially the same length. 
   
   
       13 . The earth boring bit of  claim 10 , wherein the first and second ridges are unequal in length. 
   
   
       14 . The earth boring bit of  claim 10 , wherein at least one of the ridges on an insert has a cross section that includes an edge and the other ridge on the insert has a rounded cross section. 
   
   
       15 . An earth boring bit comprising:
 a bit body;   a roller cone rotatingly attached to the bit body;   inserts on the roller cone having a leading surface and a trailing surface, the inserts oriented so that during boring operations the leading surfaces are in cutting contact with the material being displaced; and   ridges projecting outward from each leading surface to define faces on the sides of the ridges that lie in a plane oblique to the roller cone axes, so that material displaced during boring operations is urged away from the space between adjacent inserts.