Wedge thread with high-angle metal seal

1. A threaded connection, comprising:

a pin member providing a single external wedge thread comprising a first external portion and a second external portion;

a box member providing a single internal wedge thread comprising a first internal portion and a second internal portion, wherein the first and second internal portions threadably correspond with the first and second external portions;

wherein the first internal and external portions are characterized by a first wedge ratio and the second internal and external portions are characterized by a second wedge ratio, wherein the first wedge ratio is less than the second wedge ratio;

a radial metal-to-metal seal configured to seal between the pin member and the box member; and

wherein the radial metal-to-metal seal comprises a seal angle between about 4 degrees and about 15 degrees.

2. The threaded connection of claim 1 , wherein the pin and box members are configured such that, during make-up, the first external and internal portions reach a first selected make-up before engagement of the radial metal-to-metal seal and a second selected make-up of the second external and internal portions.

3. The threaded connection of claim 1 , wherein the radial metal-to-metal seal is selected from the group consisting of pin-nose seals, box-face seals, and mid-thread seals.

4. The threaded connection of claim 1 , wherein the radial metal-to-metal seal comprises a seal angle between about 7 degrees and about 14 degrees.

5. The threaded connection of claim 1 , further comprising a transition region between the first internal and external portions and the second internal and external portions.

6. The threaded connection of claim 1 , further comprising an offset between the second internal portion and the second external portion.

7. The threaded connection of claim 1 , further comprising a third portion on each of the box member and the pin member, wherein the third portions are characterized by a third wedge ratio substantially equal to the first wedge ratio.

8. A threaded connection, comprising:

a pin member providing a single external wedge thread comprising a first external portion and a second external portion;

a box member providing a single internal wedge thread comprising a first internal portion and a second internal portion, wherein the first and second internal portions threadably correspond with the first and second external portions;

wherein the first internal and external portions are characterized by a first wedge ratio and the second internal and external portions are characterized by a second wedge ratio; and

a radial metal-to-metal seal configured to seal between the pin member and the box member;

wherein the pin and box members are configured such that, during make-up, the first external and internal portions reach a first selected make-up before engagement of the radial metal-to-metal seal and a second selected make-up of the second external and internal portions.

9. The threaded connection of claim 8 , wherein the radial metal-to-metal seal is selected from the group consisting of pin-nose seals, box-shoulder seals, and mid-shoulder seals.

10. The threaded connection of claim 8 , wherein the radial metal-to-metal seal comprises a seal angle between about 4 degrees and about 15 degrees.

11. The threaded connection of claim 8 , wherein the first wedge ratio is less than the second wedge ratio.

12. The threaded connection of claim 8 , further comprising a transition region between the first internal and external portions and the second internal and external portions.

13. The threaded connection of claim 8 , further comprising an offset between the second internal portion and the second external portion.

14. The threaded connection of claim 13 , wherein the first wedge ratio and the second wedge ratio are substantially equal.

15. The threaded connection of claim 8 , wherein the radial metal-to-metal seal engages before the second selected make-up of the second internal and external portions.

16. The threaded connection of claim 8 , wherein the radial metal-to-metal seal engages simultaneously with the second selected make-up of the second external and internal portions.

17. The threaded connection of claim 8 , wherein the first specified make-up occurs when load and stab flanks of the first internal and external portions reach a specified amount of interference.

18. The threaded connection of claim 8 , wherein the second specified make-up occurs when load and stab flanks of the second internal and external portions reach a specified amount of interference.

19. A threaded connection having wedge threads, the threaded connection comprising:

a pin member comprising a continuous pin thread having a pin thread crest, a pin thread root, a pin load flank, and a pin stab flank, wherein the pin thread comprises at least a first portion, a transition region, and a second portion formed sequentially thereon;

a box member comprising a continuous box thread having a box thread crest, a box thread root, a box load flank, and a box stab flank, wherein the box thread comprises at least a first portion, a transition region, and a second portion formed sequentially thereon, the portions on the box thread corresponding generally in axial position with the portions on the pin thread;

wherein the first portion has a first wedge ratio, the transition region has a transition wedge ratio, and the second portion has a second wedge ratio;

wherein thread leads are substantially constant within each of the portions;

a radial metal-to-metal seal configured to seal between the pin member and the box member; and

wherein the pin and box members are configured such that during make-up, the first portions reach a first selected make-up before engagement of the radial metal-to-metal seal and a second selected make-up of the second portions.