Steerable underreamer/stabilizer assembly and method

1. A bottom hole assembly to drill a formation, the bottom hole assembly comprising:

a drill bit;

a drilling assembly comprising a drive mechanism and a directional mechanism;

a stabilized underreamer assembly located between the drill bit and the drilling assembly; and

at least one arm assembly extending from the stabilized underreamer assembly, the arm assembly including a stabilizer portion and an underreamer cutting structure.

2. The bottom hole assembly of claim 1 , wherein the stabilized underreamer assembly further comprises:

at least one axial recess, wherein a plurality of angled channels are formed into a wall of the at least one axial recess; and

wherein the at least one arm assembly translates along the plurality of angled channels between a collapsed position and an expanded position.

3. The bottom hole assembly of claim 1 , wherein the at least one arm assembly translates axially and radially between a collapsed position and an expanded position.

4. The bottom hole assembly of claim 1 , wherein the drive mechanism includes a positive displacement mud motor.

5. The bottom hole assembly of claim 1 , wherein the directional mechanism comprises at least one selected from the group consisting of a rotary steerable device and a bent housing.

6. The bottom hole assembly of claim 1 , wherein the stabilized underreamer assembly further comprises backreamer cutters.

7. The bottom hole assembly of claim 1 , wherein the stabilized underreamer assembly is integral with the drill bit.

8. The bottom hole assembly of claim 1 , wherein the stabilized underreamer assembly is located behind the drill bit by a distance between one to five times a cutting diameter of the drill bit.

9. The bottom hole assembly of claim 1 , further comprising an expandable stabilizer assembly located uphole of the directional mechanism of the drilling assembly.

10. The bottom hole assembly of claim 1 , wherein the underreamer cutting structure comprises at least one of the group consisting of polycrystalline diamond compact cutters, hard metal inserts, and impregnated natural diamond.

11. The bottom hole assembly of claim 1 , wherein the stabilizer portion of the arm assembly is configured to engage the formation after the underreamer cutting structure engages the formation.

12. A method to drill a formation, the method comprising:

positioning a stabilized underreamer assembly behind a drill bit, wherein at least one arm assembly of the stabilizer assembly includes an underreamer cutting structure and a stabilizer portion;

positioning a drilling assembly behind the stabilized underreamer assembly;

rotating the drill bit and stabilized underreamer assembly with the drilling assembly to penetrate the formation; and

directing a trajectory of the drill bit and stabilized underreamer assembly with a directional mechanism of the drilling assembly.

13. The method of claim 12 , wherein the stabilized underreamer assembly further comprises:

at least one axial recess, wherein a plurality of angled channels are formed into a wall of the at least one axial recess;

wherein the at least one arm assembly translates along the plurality of angled channels between a collapsed position and an expanded position.

14. The method of claim 13 , further comprising translating the at least one arm assembly along the plurality of angled channels to engage the formation with the underreamer cutting structure and the stabilizer portion.

15. The method of claim 12 , further comprising engaging the formation with the underreamer cutting structure before engaging the formation with the stabilizer portion.

16. The method of claim 12 , further comprising:

drilling a pilot bore with the drill bit; and

underreaming the formation with the stabilized underreamer assembly.

17. The method of claim 12 , wherein a directional mechanism of the drilling assembly includes at least one of the group consisting of a rotary steerable assembly, a bent housing, and an articulated sub.

18. The method of claim 12 , further comprising stabilizing the drilling assembly with an expandable stabilizer assembly.

19. A stabilized underreamer located between a directional drilling assembly and a drill bit, the stabilized underreamer comprising:

at least one arm assembly extending from the stabilized underreamer assembly, the arm assembly including a stabilizer portion and an underreamer cutting structure;

at least one axial recess, wherein a plurality of angled channels are formed into a wall of the at least one axial recess; and

wherein the at least one arm assembly translates along the plurality of angled channels between a collapsed position and an expanded position.

20. The stabilized underreamer of claim 19 , wherein the stabilizer portion is configured to engage a formation after the underreamer cutting structure engages the formation.

21. A method to directionally drill a subterranean formation, comprising assembling the stabilized underreamer of claim 19 into a bottom hole assembly.

22. A method of drilling a borehole comprising:

disposing a drill bit and a stabilized underreamer at a distal end of a drillstring;

positioning a drilling assembly behind the stabilized underreamer;

drilling a pilot bore with the drill bit and the drilling assembly;

underreaming the pilot bore with underreamer cutters of the stabilized underreamer; and

stabilizing the drill bit with stabilizer pads of the stabilized underreamer.

23. The method of claim 22 , wherein the stabilized underreamer is integrated with the drill bit.