Force-balanced roller-cone bits, systems, drilling methods, and design methods

• US 20040182609A1
• Filed: 01/27/2004
• Published: 09/23/2004
• Est. Priority Date: 08/31/1998
• Status: Abandoned Application

• Current Assignee: Shilin Chen
• Original Assignee: Shilin Chen
• Inventors: Chen, Shilin
• Application Number:
  US10/765,695
• Publication Number:
  US 20040182609A1
• Time in Patent Office: Days
• US Class Current: 175/374
• CPC Class Codes: E21B 10/08 Roller bits E21B10/26 takes precedence; roller core bits E21B10/06; characterised by wear resisting parts E21B10/50
• CPC Class Codes: E21B 10/16 characterised by tooth form or arrangement
• CPC Class Codes: E21B 49/00 Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells

Abstract

Roller cone drilling wherein the bit optimization process equalizes the downforce (axial force) for the cones (as nearly as possible, subject to other design constraints). Bit performance is significantly enhanced by equalizing downforce.

Claims

1. A roller cone drill bit, comprising:

a bit body;

three roller cones attached to said bit body and able to rotate with respect to said bit body;

a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.

2. The drill bit according to claim 1, wherein axial force exerted on the bit during drilling is substantially balanced between the cones.

3. The drill bit according to claim 1, wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed each of the other cones.

4. The drill bit according to claim 1, wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.

5. The drill bit according to claim 1, wherein a distribution of axial force on the bit is optimized.

6. The drill bit according to claim 1, wherein said cutting elements comprise superhard inserts.

7. The drill bit according to claim 1, wherein said cutting elements comprise tungsten carbide inserts.

8. The drill bit according to claim 1, wherein said cutting elements comprise milled steel teeth.

9. The drill bit according to claim 8, wherein said cutting elements further comprise hardface coating.

10. A roller cone drill bit, comprising:

a bit body;

three roller cones attached to said bit body and able to rotate with respect to said bit body;

a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a depth of penetration for the cutting elements into a formation during drilling is substantially the same for each of the cones.

11. The drill bit according to claim 10, wherein axial force exerted on the bit during drilling is substantially balanced between the cones.

12. The drill bit according to claim 10, wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.

13. The drill bit according to claim 10, wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.

14. The drill bit according to claim 10, wherein a distribution of axial force on the bit is optimized.

15. The drill bit according to claim 10, wherein said cutting elements comprise superhard inserts.

16. The drill bit according to claim 10, wherein said cutting elements comprise tungsten carbide inserts.

17. The drill bit according to claim 10, wherein said cutting elements comprise milled steel teeth.

18. The drill bit according to claim 17, wherein said cutting elements further comprise hardface coating.