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

• US 20040167762A1
• Filed: 02/26/2004
• Published: 08/26/2004
• Est. Priority Date: 08/31/1998
• Status: Abandoned Application

• Current Assignee: Shilin Chen
• Original Assignee: Shilin Chen
• Inventors: Chen, Shilin
• Application Number:
  US10/787,792
• Publication Number:
  US 20040167762A1
• Time in Patent Office: Days
• US Class Current: 703/10
• 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

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 method for designing a roller cone drill bit having a plurality of roller cones and initial design parameters, comprising:

simulating drilling an earth formation with the bit and determining as a result of the simulating, a distribution of axial force on the bit;

adjusting at least one of the initial design parameters;

repeating the simulating drilling; and

repeating the adjusting, the simulating and the determining until the distribution of axial force is optimized.

2. The method as defined in claim 1, wherein the initial design parameters comprise at least one of cutting element count on each cone, cutting element shape, a number of rows of cutting elements on each roller cone, cutting element size, location of rows of cutting elements on each cone and cutting element type.

3. The method as defined in claim 1, further comprising:

determining as a result of the simulating an axial force on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the axial force on any one of the roller cones is substantially the same as the axial force on any other one of the roller cones.

4. The method as defined in claim 1, further comprising:

determining as a result of the simulating a projected area of contact of cutting elements with the earth formation on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the projected area for any one of the roller cones is substantially the same as the projected area any other one of the roller cones.

5. The method as defined in claim 1, further comprising:

determining as a result of the simulating a work performed by each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the work performed by any one of the roller cones is substantially the same as the work performed by any other one of the roller cones.

6. The method as defined in claim 1, further comprising:

determining as a result of the simulating a depth of penetration for cutting elements on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the depth of penetration for any one of the roller cones is substantially the same as the depth of penetration for any other one of the roller cones.

7. A method for designing a roller cone drill bit having a plurality of roller cones and initial design parameters, comprising:

simulating drilling an earth formation with the bit and determining for each of the roller cones as a result of the simulating, a work performed by each roller cone;

adjusting at least one of the initial design parameters;

repeating the simulating drilling; and

repeating the adjusting, the simulating and the determining until the work performed is substantially the same for each one of the roller cones.

8. The method as defined in claim 7, further comprising:

determining as a result of the simulating a projected area of contact of cutting elements with the earth formation on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the projected area for any one of the roller cones is substantially the same as the projected area any other one of the roller cones.

9. The method as defined in claim 7, further comprising:

determining as a result of the simulating an axial force on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the axial force on any one of the roller cones is substantially the same as the axial force on any other one of the roller cones.

10. The method as defined in claim 7, wherein the initial design parameters comprise at least one of cutting element count on each cone, cutting element shape, a number of rows of cutting elements on each roller cone and cutting element type.

11. The method as defined in claim 7, further comprising:

determining as a result of the simulating a depth of penetration for cutting elements on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the depth of penetration for any one of the roller cones is substantially the same as the depth of penetration for any other one of the roller cones.

12. The method as defined in claim 7, further comprising:

determining as a result of the simulating a distribution of axial force on the bit;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the distribution of axial force on the bit is optimized.

13. A method for designing a roller cone drill bit having a plurality of roller cones and initial design parameters, comprising:

simulating drilling an earth formation with the bit and determining for each of the roller cones as a result of the simulating, a projected area of contact of cutting elements on each roller cone with the earth formation;

adjusting at least one of the initial design parameters;

repeating the simulating drilling; and

repeating the adjusting, the simulating and the determining until the projected area is substantially the same for each one of the roller cones.

14. The method as defined in claim 13, further comprising:

determining as a result of the simulating an axial force on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the axial force on any one of the roller cones is substantially the same as the axial force on any other one of the roller cones.

15. The method as defined in claim 13, wherein the initial design parameters comprise at least one of cutting element count on each cone, cutting element shape, a number of rows of cutting elements on each roller cone, cutting element size, location of each of the rows of cutting elements on each roller cone and cutting element type.

16. The method as defined in claim 13, further comprising:

determining as a result of the simulating a depth of penetration for cutting elements on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the depth of penetration for any one of the roller cones is substantially the same as the depth of penetration for any other one of the roller cones.

17. The method as defined in claim 13, further comprising:

determining as a result of the simulating a distribution of axial force on the bit;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the distribution of axial force on the bit is optimized.

18. The method as defined in claim 13, further comprising:

determining as a result of the simulating a work performed by each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the work performed by any one of the roller cones is substantially the same as the work performed by any other one of the roller cones.

19. A method for designing a roller cone drill bit having a plurality of roller cones and initial design parameters, comprising:

simulating drilling an earth formation with the bit and determining for each of the roller cones as a result of the simulating, a depth of penetration of cutting elements on each roller cone with the earth formation;

adjusting at least one of the initial design parameters;

repeating the simulating drilling; and

repeating the adjusting, the simulating and the determining until the depth of penetration is substantially the same for each one of the roller cones.

20. The method as defined in claim 19, further comprising:

determining as a result of the simulating a work performed by each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the work performed by any one of the roller cones is substantially the same as the work performed by any other one of the roller cones.

21. The method as defined in claim 19, further comprising:

determining as a result of the simulating a projected area of contact of cutting elements with the earth formation on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the projected area for any one of the roller cones is substantially the same as the projected area any other one of the roller cones.

22. The method as defined in claim 19, further comprising:

determining as a result of the simulating an axial force on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the axial force on any one of the roller cones is substantially the same as the axial force on any other one of the roller cones.

23. The method as defined in claim 19, further comprising:

determining as a result of the simulating a distribution of axial force on the bit;

adjusting at least one of the initial design parameters;

repeating the simulating and determining; and

repeating the adjusting, simulating and determining until the distribution of axial force on the bit is optimized.

24. The method as defined in claim 19, wherein the initial design parameters comprise at least one of cutting element count on each cone, cutting element shape, a number of rows of cutting elements on each roller cone, cutting element size, location of each of the rows of cutting elements on each roller cone and cutting element type.

25. A method for designing a roller cone drill bit having a plurality of roller cones and initial design parameters, comprising:

simulating drilling an earth formation with the bit;

determining as a result of the simulating an axial force on each one of the roller cones;

adjusting at least one of the initial design parameters;

repeating the simulating drilling; and

repeating the adjusting, the simulating and the determining until the axial force on any of the roller cones is substantially the same as the axial force on any other one of the roller cones.