Fixed cutter drill bits with tailored gage pads for directional drilling

Abstract

A fixed cutter drill bit for drilling a borehole in an earthen formation includes a bit body having a central axis and a bit face. The bit body is configured to rotate about the central axis in a cutting direction of rotation. The bit face includes a concave cone region extending radially from the central axis, a convex shoulder region extending radially from the cone region, a nose at the intersection of the cone region and the shoulder region, and a gage region extending radially from the shoulder region to a full gage diameter of the drill bit. In addition, the drill bit includes a cutting structure disposed on the bit face. The cutting structure includes a primary blade extending radially from proximal the bit axis through the cone region and the shoulder region to the gage region. The blade has a leading side relative to the cutting direction of rotation, a trailing side relative to the cutting direction of rotation, and a cutter-supporting surface extending from the leading side to the trailing side. Further, the drill bit includes a plurality of cutter elements mounted to the cutter-supporting surface of the primary blade in the cone region, the shoulder region, and the gage region. Still further, the drill bit includes a gage pad disposed in the gage region and extending axially from the primary blade. The gage pad has a central axis, an uphole end distal the primary blade, a downhole end integral with the primary blade, a leading lateral side relative to the cutting direction of rotation, a trailing lateral side relative to the cutting direction of rotation, and a formation facing surface configured to slidingly engage a sidewall of the borehole during drilling. The formation facing surface of the gage pad extends axially from the uphole end to the downhole end of the gage pad, and wherein the formation facing surface extends laterally from the leading side of the gage pad to the trailing side of the gage pad. The gage pad includes a surface area reducing feature positioned along a middle portion of the gage pad that is axially positioned between and axially spaced from the uphole end of the gage pad and the downhole end of the gage pad. The surface area reducing feature comprises a first recess extending from the formation facing surface toward the bit body.

What is claimed is: 
     
         1 . A fixed cutter drill bit for drilling a borehole in an earthen formation, the drill bit comprising:
 a bit body having a central axis and a bit face, wherein the bit body is configured to rotate about the central axis in a cutting direction of rotation, wherein the bit face includes a concave cone region extending radially from the central axis, a convex shoulder region extending radially from the cone region, a nose at the intersection of the cone region and the shoulder region, and a gage region extending radially from the shoulder region to a full gage diameter of the drill bit;   a cutting structure disposed on the bit face, wherein the cutting structure includes a primary blade extending radially from proximal the bit axis through the cone region and the shoulder region to the gage region, wherein the blade has a leading side relative to the cutting direction of rotation, a trailing side relative to the cutting direction of rotation, and a cutter-supporting surface extending from the leading side to the trailing side; and   a plurality of cutter elements mounted to the cutter-supporting surface of the primary blade in the cone region, the shoulder region, and the gage region;   a gage pad disposed in the gage region and extending axially from the primary blade, wherein the gage pad has a central axis, an uphole end distal the primary blade, a downhole end integral with the primary blade, a leading lateral side relative to the cutting direction of rotation, a trailing lateral side relative to the cutting direction of rotation, and a formation facing surface configured to slidingly engage a sidewall of the borehole during drilling;   wherein the formation facing surface of the gage pad extends axially from the uphole end to the downhole end of the gage pad, and wherein the formation facing surface extends laterally from the leading side of the gage pad to the trailing side of the gage pad;   wherein the gage pad includes a surface area reducing feature positioned along a middle portion of the gage pad that is axially positioned between and axially spaced from the uphole end of the gage pad and the downhole end of the gage pad, wherein the surface area reducing feature comprises a first recess extending from the formation facing surface toward the bit body.   
     
     
         2 . The drill bit of  claim 1 , wherein the first recess extends laterally from the leading side of the gage pad or the trailing side of the gage pad. 
     
     
         3 . The drill bit of  claim 1 , wherein the first recess is laterally positioned between and laterally spaced from the leading side of the gage pad and the trailing side of the gage pad. 
     
     
         4 . The drill bit of  claim 1 , wherein the surface area reducing feature comprises a second recess extending from the formation facing surface toward the bit body. 
     
     
         5 . The drill bit of  claim 4 , wherein the first recess extends laterally from the leading side of the gage pad and the second recess extends laterally from the trailing side of the gage pad. 
     
     
         6 . The drill bit of  claim 1 , wherein the surface area reducing feature comprises a plurality of recesses including the first recess, wherein each of the plurality of recesses extends from the formation facing surface toward the bit body. 
     
     
         7 . The drill bit of  claim 6 , wherein the plurality of recesses are laterally positioned between and laterally spaced apart from the leading side of the gage pad and the trailing side of the gage pad. 
     
     
         8 . The drill bit of  claim 1 , wherein the gage pad is I-shaped in side view perpendicular to the central axis of the gage pad. 
     
     
         9 . The drill bit of  claim 1 , wherein the leading side of the gage pad is oriented parallel to the trailing side of the gage pad. 
     
     
         10 . The drill bit of  claim 1 , wherein the leading side of the gage pad and the trailing side of the gage pad taper toward or away from moving axially relative to the central axis of the gage pad from the downhole end of the gage pad to the uphole end of the gage pad. 
     
     
         11 . The drill bit of  claim 1 , wherein the formation facing surface has a width measured perpendicularly from the leading side of the gage pad to the trailing side of the gage pad, wherein the width of the formation facing surface along the middle portion of the gage pad is less than the width of the formation facing surface at the uphole end and less than the width of the formation facing surface at the downhole end. 
     
     
         12 . The drill bit of  claim 1 , wherein the formation facing surface of the gage pad is disposed at the full gage diameter of the drill bit along an entire axial length of the gage pad measured axially relative to the central axis of the gage pad from the uphole end of the gage pad to the downhole end of the gage pad. 
     
     
         13 . The drill bit of  claim 1 , wherein the formation facing surface of the gage pad is oriented at an acute angle β relative to the central axis of the bit body. 
     
     
         14 . The drill bit of  claim 13 , wherein the formation facing surface of the gage pad slopes radially inwardly relative to the central axis of the bit body moving axially relative to the central axis of the gage pad from the downhole end of the gage pad to the uphole end of the gage pad. 
     
     
         15 . The drill bit of  claim 1 , wherein the downhole end of the gage pad is disposed at the full gage diameter of the drill bit and the uphole end of the gage pad is radially spaced from the full gage diameter of the drill bit. 
     
     
         16 . A fixed cutter drill bit for drilling a borehole in an earthen formation, the drill bit comprising:
 a bit body having a central axis and a bit face, wherein the bit body is configured to rotate about the central axis in a cutting direction of rotation, wherein the bit face includes a concave cone region extending radially from the central axis, a convex shoulder region extending radially from the cone region, a nose at the intersection of the cone region and the shoulder region, and a gage region extending radially from the shoulder region to a full gage diameter of the drill bit;   a cutting structure disposed on the bit face, wherein the cutting structure includes a primary blade extending radially from proximal the bit axis through the cone region and the shoulder region to the gage region, wherein the blade has a leading side relative to the cutting direction of rotation, a trailing side relative to the cutting direction of rotation, and a cutter-supporting surface extending from the leading side to the trailing side; and   a plurality of cutter elements mounted to the cutter-supporting surface of the primary blade;   a gage pad disposed in the gage region and extending axially from the primary blade, wherein the gage pad has a central axis, an uphole end distal the primary blade, a downhole end integral with the primary blade, a leading lateral side relative to the cutting direction of rotation, a trailing lateral side relative to the cutting direction of rotation, and a formation facing surface configured to slidingly engage a sidewall of the borehole during drilling;   wherein the formation facing surface of the gage pad extends axially from the uphole end to the downhole end of the gage pad;   wherein the gage pad is I-shaped in side view perpendicular to the central axis of the gage pad.   
     
     
         17 . The drill bit of  claim 16 , wherein the gage pad includes:
 a first recess extending laterally from the leading side of the gage pad and extending radially from the formation facing surface;   a second recess extending laterally from the trailing side of the gage pad and extending radially from the formation facing surface.   
     
     
         18 . The drill bit of  claim 17 , wherein each recess has a rectangular shape. 
     
     
         19 . The drill bit of  claim 18 , wherein the first recess includes a first planar surface extending laterally from the leading end, a second planar surface extending laterally from the leading end, and a base planar surface extending axially from the first planar surface of the first recess to the second planar surface of the first recess;
 wherein the second recess includes a first planar surface extending laterally from the trailing end, a second planar surface extending laterally from the trailing end, and a base planar surface extending axially from the first planar surface of the second recess to the second planar surface of the second recess.   
     
     
         20 . The drill bit of  claim 17 , wherein each recess is axially spaced from the uphole and the downhole end. 
     
     
         21 . The drill bit of  claim 16 , wherein the leading side is oriented parallel to the trailing side. 
     
     
         22 . The drill bit of  claim 16 , wherein the leading side and the trailing side slope toward each other or away from each other moving axially from the uphole end of the gage pad to the downhole end of the gage pad. 
     
     
         23 . The drill bit of  claim 16 , wherein the formation facing surface of the gage pad is disposed at the full gage diameter of the drill bit along an entire axial length of the gage pad measured axially relative to the central axis of the gage pad from the uphole end of the gage pad to the downhole end of the gage pad. 
     
     
         24 . The drill bit of  claim 16 , wherein the formation facing surface of the gage pad is oriented at an acute angle β relative to the central axis of the bit body, and wherein the formation facing surface of the gage pad slopes radially inwardly relative to the central axis of the bit body moving axially relative to the central axis of the gage pad from the downhole end of the gage pad to the uphole end of the gage pad. 
     
     
         25 . The drill bit of  claim 16 , wherein the downhole end of the gage pad is disposed at the full gage diameter of the drill bit and the uphole end of the gage pad is radially spaced from the full gage diameter of the drill bit.