Earth-boring tools including rotatable cutting elements and formation-engaging features that drive rotation of such cutting elements, and related methods

Abstract

An earth-boring tool includes a body and cutting elements rotatably mounted on the body. The earth-boring tool also includes a formation-engaging feature attached to the body and exposed at a face of the body. The formation-engaging feature may be configured to rotate about an axis of rotation responsive to frictional forces acting between the formation-engaging feature and a formation when the body moves relative to the formation. The axis of rotation of the formation-engaging feature may be oriented at an angle to an axis of rotation of the cutting elements. The formation-engaging feature may be operably coupled to the cutting elements such that rotation of the formation-engaging feature causes rotation of the cutting elements. Methods include drilling a subterranean formation including engaging a formation with the cutting elements and the formation-engaging features.

1 . An earth-boring tool for drilling a subterranean formation, comprising:
 a body;   at least one cutting element rotatably mounted on the body, the at least one cutting element comprising a table of polycrystalline hard material having an end cutting surface and a supporting substrate;   a formation-engaging feature attached to the body and exposed at a face of the body, the formation-engaging feature configured to rotate about an axis of rotation responsive to frictional forces acting between the formation-engaging feature and a formation when the body moves relative to the formation, wherein the axis of rotation of the formation-engaging feature is oriented at an angle to an axis of rotation of the at least one cutting element; and   wherein the formation-engaging feature is operably coupled to the at least one cutting element such that rotation of the formation-engaging feature causes rotation of the at least one cutting element.   
     
     
         2 . The earth-boring tool of  claim 1 , further comprising:
 a first shaft extending from the formation-engaging feature and carrying a first gear; and   a second shaft extending from the at least one cutting element and carrying a second gear; and   wherein the first gear is engaged with the second gear.   
     
     
         3 . The earth-boring tool of  claim 2 , wherein each of the first gear and the second gear comprises a miter gear. 
     
     
         4 . The earth-boring tool of  claim 2 , wherein the first gear has a diameter greater than a diameter of the second gear. 
     
     
         5 . The earth-boring tool of  claim 2 , wherein the first gear has a first tooth pattern, and the second gear has a second tooth pattern, the second tooth pattern differing from the first tooth pattern. 
     
     
         6 . The earth-boring tool of  claim 2 , wherein an axis of rotation of the first shaft is substantially aligned with the axis of rotation of the formation-engaging feature, and an axis of rotation of the second shaft is substantially aligned with the axis of rotation of the at least one cutting element, and wherein the axis of rotation of the first shaft is generally perpendicular to the axis of rotation of the second shaft. 
     
     
         7 . The earth-boring tool of  claim 1 , wherein the body comprises at least one blade having a recess therein, and the formation-engaging feature is mounted at least partially within the recess. 
     
     
         8 . The earth-boring tool of  claim 1 , wherein the formation-engaging feature comprises a first rotational body and a second rotational body, the first rotational body of the formation-engaging feature being configured to rotate responsive to frictional forces acting between the first rotational body and the formation when the body moves relative thereto, and the second rotational body being configured to rotate responsive to rotation of the first rotational body. 
     
     
         9 . The earth-boring tool of  claim 8 , wherein the first rotational body of the formation-engaging feature is operably coupled to the second rotational body of the formation-engaging feature by at least one of grooves, teeth, or frictional. 
     
     
         10 . The earth-boring tool of  claim 1 , wherein the formation-engaging feature is operably coupled to the at least one cutting element such that one full revolution of the formation-engaging feature results in less than one full revolution of the at least one cutting element. 
     
     
         11 . An earth-boring rotary drill bit, comprising:
 a bit body;   a cutting element mounted on the bit body, the cutting element comprising a table of polycrystalline hard material having an end cutting surface and a supporting substrate, the cutting element being rotatable about a rotational axis;   a formation-engaging feature attached to the bit body and exposed at a face of the bit body and configured to rotate about an axis of rotation responsive to frictional forces acting between the formation-engaging feature and a subterranean formation when the bit body moves relative to the subterranean formation, wherein the axis of rotation of the formation-engaging feature is oriented at an angle to an axis of rotation of the cutting element; and   a flexible drive shaft operably coupled between the formation-engaging feature and the supporting substrate of the cutting element, the flexible drive shaft configured to apply torque to the supporting substrate of the cutting element so as to rotate the cutting element responsive to rotation of the formation-engaging feature.   
     
     
         12 . The earth-boring rotary drill bit of  claim 11 , further comprising a plurality of rotatable cutting elements mounted on the bit body and a plurality of rotatable formation-engaging features attached to the bit body and exposed at a face of the bit body, each rotatable formation-engaging feature of the plurality of formation-engaging features being operably coupled with a respective one of the plurality of rotatable cutting elements such that rotation of each rotatable formation-engaging feature of the plurality of formation-engaging features drives rotation of a respective cutting element. 
     
     
         13 . The earth-boring rotary drill bit of  claim 11 , wherein the face of the bit body includes a cone region, a nose region, a shoulder region, and a gage region, and wherein the cutting element is located in the shoulder region or the gage region of the face of the bit body. 
     
     
         14 . The earth-boring rotary drill bit of  claim 11 , wherein the bit body includes blades having a leading edge, the cutting element is mounted at the leading edge of one of the blades, and the formation-engaging feature is located rotationally behind the cutting element. 
     
     
         15 . The earth-boring rotary drill bit of  claim 11 , wherein the flexible drive shaft comprises non-alloy carbon steel material. 
     
     
         16 . A method of drilling a subterranean formation, comprising:
 applying weight-on-bit to an earth-boring tool substantially along a longitudinal axis thereof and rotating the earth-boring tool;   engaging a formation with a plurality of rotatable cutting elements located on blades of a bit body of the earth-boring tool, wherein the plurality of rotatable cutting elements are rotatably secured within pockets of the blades;   engaging the formation with a formation-engaging feature attached to the bit body and exposed at a face of the earth-boring tool and configured to rotate about an axis of rotation thereof responsive to frictional forces acting between the formation-engaging feature and the formation when the earth-boring tool moves relative thereto; and   driving rotation of at least one cutting element of the plurality of rotatable cutting elements responsive to rotation of the formation-engaging feature, wherein the axis of rotation of the formation-engaging feature is oriented at an angle to an axis of rotation of the at least one cutting element.   
     
     
         17 . The method of  claim 16 , wherein driving rotation of the plurality of rotatable cutting elements comprises rotating a first shaft extending from the formation-engaging feature and carrying a first gear and rotating a second shaft extending from the at least one cutting element and carrying a second gear, wherein the first gear is engaged with the second gear. 
     
     
         18 . The method of  claim 17 , wherein rotating the first shaft extending from the formation-engaging feature and carrying the first gear and rotating a second shaft extending from the at least one cutting element and carrying the second gear comprises the first gear having a diameter greater than a diameter of the second gear. 
     
     
         19 . The method of  claim 16 , wherein the axis of rotation of the formation-engaging feature is perpendicular to an axis of rotation of the at least one cutting element. 
     
     
         20 . The method of  claim 16 , wherein rotating the formation-engaging feature through one full revolution of the formation-engaging feature results in less than one full revolution of the at least one cutting element. 
     
     
         21 . The method of  claim 16 , wherein engaging the formation with the formation-engaging feature comprises controlling a rate at which the formation-engaging feature extends and retracts from the face of the earth-boring tool using a hydraulic actuation device.