Earth-boring tools including movable formation-engaging structures and related methods

1. An earth-boring tool, comprising:

a body comprising a plurality of radially projecting and longitudinally extending blades rotationally separated by junk slots;

a cutting element attached to one of the plurality of blades of the body at a first location; and

a formation-engaging structure attached to the one of the plurality of blades of the body at a second location, the formation-engaging structure being movable during a drilling operation between a first position and a second position, the formation-engaging structure located on the one of the plurality of blades at a first radial distance from a longitudinal axis of the body at which the cutting element will at least initially shield the formation-engaging structure from engaging a formation, a height of the cutting element above the one of the plurality of blades being greater than an exposure of the formation-engaging structure, and the formation-engaging structure located rotationally behind and at least partially within a cutting path traversed by the cutting element when the formation-engaging structure is in the first position, the formation-engaging structure located at a different second radial distance from the longitudinal axis of the body at which the formation-engaging structure is located adjacent to the cutting path traversed by the cutting element to engage a formation when the formation-engaging structure is in the second position.

2. The earth-boring tool of claim 1 , wherein the cutting element is attached to the body at an immovable fixed location.

3. The earth-boring tool of claim 2 , wherein the immovable fixed location is at a rotationally leading edge of the one of the plurality of blades.

4. The earth-boring tool of claim 1 , wherein the formation-engaging structure rotates as the formation-engaging structure moves from the first position to the second position.

5. The earth-boring tool of claim 1 , wherein the formation-engaging structure comprises an additional cutting element.

6. The earth-boring tool of claim 5 , wherein the additional cutting element rotates as the additional cutting element moves from the first position to the second position.

7. The earth-boring tool of claim 6 , wherein a central axis of the additional cutting element is located in a plane oriented at an acute angle to the direction of movement of the additional cutting element relative to a formation when the additional cutting element is in the first position and the earth-boring tool is used to cut a bore in the formation.

8. The earth-boring tool of claim 7 , wherein the central axis of the additional cutting element and the direction of movement of the additional cutting element relative to a formation lie in a common plane when the additional cutting element is in the second position and the earth-boring tool is used to cut a bore in the formation.

9. The earth-boring tool of claim 1 , wherein the formation-engaging structure is mounted to a support member, the support member disposed at least partially within a recess in the body.

10. The earth-boring tool of claim 9 , wherein the support member is configured to rotate relative to the body to move the formation-engaging structure from the first position to the second position.

11. The earth-boring tool of claim 10 , wherein the support member is generally cylindrical, at least a portion of the support member configured to rotate relative to the body about a longitudinal axis of the support member to move the formation-engaging structure from the first position to the second position.

12. The earth-boring tool of claim 11 , wherein the formation-engaging structure is mounted on a longitudinal end of the generally cylindrical support member at a location offset from the longitudinal axis of the support member.

13. The earth-boring tool of claim 1 , further comprising an actuation device configured to move the formation-engaging structure from the first position to the second position.

14. The earth-boring tool of claim 13 , wherein the actuation device comprises at least one of an electro-mechanical device and an electro-hydraulic device.

15. The earth-boring tool of claim 13 , wherein the actuation device is configured to allow a pressure of drilling fluid flowing through the earth-boring tool to move the formation-engaging structure from the first position to the second position.

16. A method of forming an earth-boring tool, comprising:

attaching a cutting element to one of a plurality of radially projecting and longitudinally extending blades rotationally separated by junk slots of a body at a first location; and

attaching a movable formation-engaging structure to the one of the plurality of blades of the body at a second location, the movable formation-engaging structure being movable during a drilling operation between a first position and a second position, the formation-engaging structure located on the one of the plurality of blades at a first radial distance from a longitudinal axis of the body at which the cutting element will at least initially shield the formation-engaging structure from engaging a formation, a height of the cutting element above the one of the plurality of blades being greater than an exposure of the formation-engaging structure, and the formation-engaging structure located rotationally behind and at least partially within a cutting path traversed by the cutting element when the formation-engaging structure is in the first position, the formation-engaging structure located at a different second radial distance from the longitudinal axis of the body at which the formation-engaging structure is located adjacent to the cutting path traversed by the cutting element to engage a formation when the formation-engaging structure is in the second position.

17. The method of claim 16 , further comprising configuring the formation-engaging structure to rotate as the formation-engaging structure moves from the first position to the second position.

18. The method of claim 17 , further comprising selecting the formation-engaging structure to comprise an additional cutting element.

19. A method of drilling a wellbore using an earth-boring tool, comprising:

drilling a first section of a wellbore in a formation using an earth-boring tool including a cutting element attached to one of a plurality of radially projecting and longitudinally extending blades rotationally separated by junk slots of a body of the earth-boring tool at a first location and a movable formation-engaging structure attached to the one of the plurality of blades of the body at a second location while the movable formation-engaging structure is in a first position in which the formation-engaging structure is located on the one of the plurality of blades at a first radial distance from a longitudinal axis of the body and the cutting element at least initially shields the formation-engaging structure from engagement with the formation, a height of the cutting element above the one of the plurality of blades being greater than an exposure of the formation-engaging structure, and the formation-engaging structure located rotationally behind and at least partially within a cutting path traversed by the cutting element;

moving the formation-engaging structure from the first position to a second position at which the formation-engaging structure is located at a different second radial distance from the longitudinal axis of the body and is located adjacent to the cutting path traversed by the cutting element to engage the formation; and

drilling a second section of the wellbore in the formation using the earth-boring tool while the formation-engaging structure is in the second position and engages the formation.

20. The method of claim 19 , further comprising selecting the formation-engaging structure to comprise an additional cutting element.