Methods for modeling, designing, and optimizing the performance of drilling tool assemblies

• US 20050096847A1
• Filed: 07/09/2004
• Published: 05/05/2005
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Smith International Incorporated (Schlumberger NV)
• Original Assignee: Smith International Incorporated (Schlumberger NV)
• Inventors: Huang, Sujian
• Granted Patent: US 9,482,055 B2
• Time in Patent Office: Days
• US Class Current: 702/9
• CPC Class Codes: E21B 10/16 characterised by tooth form or arrangement
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions

Abstract

A method for designing a drilling tool assembly, having a drill bit disposed at one end includes defining initial drilling tool assembly design parameters; calculating a dynamic response of the drilling tool assembly; adjusting a value of a drilling tool assembly design parameter; and repeating the calculating and the adjusting until a drilling tool assembly performance parameter is optimized.

Claims

1. A method for determining a performance of a drilling tool assembly, comprising:

(a) generating a geometric model of the drilling tool assembly and a geometric well trajectory model of a earth formation;

(b) simulating the drilling tool assembly drilling the earth formation;

(c) determining the drilling tool assembly interaction with the earth formation; and

(d) determining forces acting on a drill bit in the drilling tool assembly.

2. The method of claim 1, wherein the determining the drilling tool assembly interaction with the earth formation is based on empirical data.

3. The method of claim 1, further comprising graphically displaying at least one of the drill tool assembly interaction with the earth formation and the forces acing on the drill bit.

4. The method of claim 3, further comprising adjusting a parameter of the drilling tool assembly based on the graphically displaying, and repeating the simulating, the determining the drilling tool assembly interaction, and the determining the forces acting on the drill bit.

5. The method of claim 1, wherein the drill bit is a fixed cutter drill bit.

6. The method of claim 1, wherein the drill bit is a roller cone drill bit.

7. The method of claim 1, wherein the drilling tool assembly comprises drill string sections and a bottom-hole assembly.

8. The method of claim 1, wherein the simulation is performed with a constant weight on bit or a constant rate of penetration.

9. The method of claim 1, wherein the simulating comprises:

(a) incrementally rotating the drill tool assembly in the earth formation; and

(b) calculating an interference between the drilling tool assembly and the earth formation during the incremental rotation.

10. The method of claim 9, wherein the calculating the interference between the drilling tool assembly and the earth formation comprises

(a) determining interferences between cutting elements on the drill bit and the earth formation;

and

(b) determining forces acting on the cutting elements based on the determined interferences.

11. The method of claim 10, wherein the determining the forces acting on the cutting elements comprises determining from a collection of cutter/formation interaction data resulting forces on the cutting elements during the incremental rotation.

12. The method of claim 10, further comprising updating cuts from the earth formation based on the interferences between the cutting elements and the earth formation during the incremental rotation.

13. The method of claim 12, further comprising repeating the steps of:

the incrementally rotating, the calculating the interferences between the cutting elements and the earth formation, the determining the forces acting on the cutting elements, and the updating the cuts from the earth formation, a number of times to determine the performance of the drill tool assembly during drilling.

14. The method of claim 12, further comprising outputting a graphical representation of at least one selected from the group consisting of a bottomhole profile of the earth formation, the drilling tool assembly, the drill bit, and the cutting elements.

15. The method of claim 14, wherein the graphical representation comprises forces acting on at least one selected from the group consisting of the cutting elements, the drill bit, and the drilling tool assembly.

16. The method of claim 10, further comprising:

calculating cutter wears based on the forces on the cutting elements, the interferences between the cutting elements and the earth formation, and a wear model; and

modifying a shape of the cutters based on the calculated cutter wears.

17. The method of claim 16, wherein the wear model comprises data in the collection of cutter/formation interaction data that is reflective of wears on the cutting elements.

18. The method of claim 11, wherein the collection of cutter/formation interaction data comprises data obtained from laboratory tests involving an engagement of a similar cutter similar to one of the cutters on the bit and a similar formation similar to said earth formation represented as drilled.

19. The method of claim 18, wherein the data is arranged in a database and forces corresponding to said interference determined by retrieving data from a record in said database having parameters of said engagement most similar to parameters calculated for the interference.

20. The method of claim 11, wherein the collection of cutter/formation interaction data comprises data obtained from a numerical model of the cutting interaction between a particular cutter and a particular formation, the numerical model developed to specifically characterize the interaction between the particular cutter similar to one of the cutters on the bit and the particular formation similar to said earth formation represented as drilled.

43. A drilling assembly designed using methods of claim 1, 21, 31, or 37.

21. A method for analyzing a drilling tool assembly design, comprising:

calculating a response of the drilling tool assembly including a response of a drill bit disposed at one end of the drilling tool assembly;

adjusting a value of at least one drilling tool assembly design parameter; and

repeating the calculating.

22. The method of claim 21, wherein the calculating comprises,

solving for the dynamic response of the drilling tool using a mechanics analysis model, and

repeating said solving for a select number of successive incremental rotations.

23. The method of claim 22, wherein said solving comprises,

constructing the mechanics analysis model of the drilling tool assembly using selected drilling tool assembly design parameters,

determining wellbore constraints from wellbore trajectory parameters, a specified bottom hole geometry, and a specified hook load,

determining loads on the drilling tool assembly for a position of the drilling tool assembly in the wellbore using at least the mechanics analysis model and the wellbore constraints, and

calculating the dynamic response of the drilling tool assembly under the loads using the mechanics analysis model.

24. The method of claim 23, wherein said solving further comprises,

redetermining the loads on the drilling tool assembly based on the calculated dynamic response to the incremental rotation,

repeating the calculating the dynamic response of the drilling tool assembly under the loads to the incremental rotation, and

repeating the redetermining and the calculating until convergence of the dynamic response is determined.

25. The method of claim 21, further comprising displaying graphical representation of the calculated response to a design engineer.

26. The method of claim 25, wherein the adjusting the value of at least one drilling tool assembly design parameter is based on the displayed graphical representation.

27. The method of claim 26, wherein the calculating, the adjusting, and the repeating are repeated until a drilling tool assembly performance parameter is optimized.

28. The method of claim 21, wherein the calculating, the adjusting, and the repeating are repeated until a drilling tool assembly performance parameter is optimized.

29. The method of claim 21, wherein the drill bit is a fixed cutter drill bit.

30. The method of claim 21, wherein the drill bit is a roller cone drill bit.

31. A method for determining at least one optimal drilling operating parameter for a drilling tool assembly that includes a drill bit disposed at one end, comprising:

calculating a dynamic response of the drilling tool assembly;

adjusting a value of at least one drilling operating parameter based on the dynamic response; and

repeating the calculating and the adjusting until a drilling performance parameter is optimized.

32. The method of claim 31, wherein the drilling performance parameter is selected from the group consisting of a rate of penetration, a rotary speed, a weight on bit, a forces on bit, and a wear on bit.

35. The method of claim 31, wherein the drill bit is a fixed cutter drill bit.

36. The method of claim 31, wherein the drill bit is a roller cone drill bit.

33. The method of 31, further comprising graphically displaying the calculated dynamic response.

34. The method of claim 33, wherein the adjusting is based on the graphically displayed dynamic response.

37. A method for designing a drilling tool assembly, having a drill bit disposed at one end, comprising:

defining initial drilling tool assembly design parameters;

calculating a dynamic response of the drilling tool assembly;

adjusting a value of a drilling tool assembly design parameter; and

repeating the calculating and the adjusting until a drilling tool assembly performance parameter is optimized.

38. The method of claim 37, wherein the drilling tool assembly design parameter comprises one selected from the group consisting of drill string parameters, bottom-hole assembly parameters, and drill bit parameters.

39. The method of claim 37, further comprising graphically displaying the calculated dynamic response.

41. The method of claim 37, wherein the drill bit is a fixed cutter drill bit.

42. The method of claim 37, wherein the drill bit is a roller cone drill bit.

40. The method of 39, wherein the adjusting is based on the graphically displayed dynamic response.