Matching of primary cutter with backup cutter

Abstract

A multi-layer downhole drilling tool designed for drilling a wellbore including a plurality of formations is disclosed, including a bit body; blades disposed on exterior portions of the bit body; first layer cutting elements disposed on the exterior portions of the blades, the first layer cutting elements extending a first distance along a first direction and a second distance along a second direction, the first direction orthogonal to the second direction, wherein the first distance is less than the second distance; and second layer cutting elements disposed on the exterior portions of the blades, at least one of the second layer cutting elements track set with one first layer cutting element and the second layer cutting elements extending a third distance along the first direction and a fourth distance along the second direction, the third distance is greater than or equal to the first distance.

What is claimed is: 
     
         1 . A multi-layer downhole drilling tool designed for drilling a wellbore including a plurality of formations, comprising:
 a bit body;   a plurality of blades disposed on exterior portions of the bit body;   a plurality of first layer cutting elements disposed on the exterior portions of the blades, each of the first layer cutting elements extending a first distance along a first direction and a second distance along a second direction, the first direction orthogonal to the second direction, wherein the first distance is less than the second distance; and   a plurality of second layer cutting elements disposed on the exterior portions of the blades, at least one of the second layer cutting elements track set with one first layer cutting element and each of the second layer cutting elements extending a third distance along the first direction and a fourth distance along the second direction, wherein the third distance is greater than or equal to the first distance,   wherein the at least one of the second layer cutting elements track set with the at least one first layer cutting element is larger than the first layer cutting element is arranged such that the second layer cutting element engages the formation when the track set first layer cutting element is sufficiently worn.   
     
     
         2 . The drilling tool of  claim 1 , wherein each of the plurality of second layer cutting elements is track set with one first layer cutting element. 
     
     
         3 . The drilling tool of  claim 1 , wherein the at least one second layer cutting element is larger than the track set first layer cutting element. 
     
     
         4 . The drilling tool of  claim 2 , wherein each second layer cutting element track set with a first layer cutting element is larger than the track set first layer cutting element. 
     
     
         5 . The drilling tool of  claim 1 , wherein the at least one second layer cutting element has a rectangular geometric shape, with distal ends of the geometric shape along the second direction having an arc and the track set first layer cutting element has a rectangular geometric shape, with distal ends of the rectangular geometric shape along the second direction having an arc. 
     
     
         6 . The drilling tool of  claim 2 , wherein each second layer cutting element track set with a first layer cutting element has a rectangular geometric shape, with distal ends of the geometric shape along the second direction having an arc and each track set first layer cutting element has a rectangular geometric shape, with distal ends of the rectangular geometric shape along the second direction having an arc. 
     
     
         7 . The drilling tool of  claim 1 , wherein the at least one second layer cutting element has a circular geometric shape that is truncated along the first direction and the track set first layer cutting element has a circular geometric shape that is truncated along the first direction. 
     
     
         8 . The drilling tool of  claim 2 , wherein each second layer cutting element track set with a first layer cutting element has a circular geometric shape that is truncated along the first direction and each track set first layer cutting element has a circular geometric shape that is truncated along the first direction. 
     
     
         9 . The drilling tool of  claim 1 , wherein the at least one second layer cutting element has a circular geometric shape, and the track set first layer cutting element has an elliptical geometric shape. 
     
     
         10 . The drilling tool of  claim 2 , wherein each second layer cutting element track set with a first layer cutting element has a circular geometric shape, and each track set first layer cutting element has an elliptical geometric shape. 
     
     
         11 . The drilling tool of  claim 1 , wherein the at least one second layer cutting element has a first elliptical geometric shape, and the track set first layer cutting element has a second elliptical geometric shape. 
     
     
         12 . The drilling tool of  claim 2 , wherein each second layer cutting element track set with a first layer cutting element has a first elliptical geometric shape, and each track set first layer cutting element has a second elliptical geometric shape. 
     
     
         13 . The drilling tool of  claim 1 , wherein one of the at least one second layer cutting element or the track set first layer cutting element has a conical shape and the other has a circular geometric shape or an elliptical geometric shape. 
     
     
         14 . The drilling tool of  claim 2 , where, for each second layer cutting element and its track set first layer cutting element, one of the second layer cutting element and the track set first layer cutting element has a conical shape and the other has a circular geometric shape or an elliptical geometric shape. 
     
     
         15 . The drilling tool of  claim 1 , wherein the second distance is greater than or equal to the fourth distance. 
     
     
         16 . A downhole drilling system, comprising:
 a drill string;   a drill bit coupled to the drill string, the drill bit including:
 a bit body; 
 a plurality of blades disposed on exterior portions of the bit body; 
 a plurality of first layer cutting elements disposed on the exterior portions of the blades, each of the first layer cutting elements extending a first distance along a first direction and a second distance along a second direction, the first direction orthogonal to the second direction, wherein the first distance is less than the second distance; and 
 a plurality of second layer cutting elements disposed on the exterior portions of the blades, at least one of the second layer cutting elements track set with one first layer cutting element and each of the second layer cutting elements extending a third distance along the first direction and a fourth distance along the second direction, wherein the third distance is greater than or equal to the first distance, 
 wherein the at least one of the second layer cutting elements track set with the at least one first layer cutting element is larger than the first layer cutting element is arranged such that the second layer cutting element engages the formation when the track set first layer cutting element is sufficiently worn. 
   
     
     
         17 . The drilling system of  claim 16 , wherein each of the plurality of second layer cutting elements is track set with one first layer cutting element. 
     
     
         18 . The drilling system of  claim 16 , wherein the at least one second layer cutting element is larger than the track set first layer cutting element. 
     
     
         19 . The drilling system of  claim 18 , wherein each second layer cutting element track set with a first layer cutting element is larger than the track set first layer cutting element. 
     
     
         20 . The drilling system of  claim 16 , wherein the at least one second layer cutting element has a rectangular geometric shape, with distal ends of the geometric shape along the second direction having an arc and the track set first layer cutting element has a rectangular geometric shape, with distal ends of the rectangular geometric shape along the second direction having an arc.