PDC drill bit with cutter design optimized with dynamic centerline analysis and having dynamic center line trajectory

• US 20060167668A1
• Filed: 01/24/2005
• Published: 07/27/2006
• Est. Priority Date: 01/24/2005
• Status: Abandoned Application

• Current Assignee: Smith International Incorporated (Schlumberger NV)
• Original Assignee: Smith International Incorporated (Schlumberger NV)
• Inventors: Durairajan, Bala, Huang, Sujian J., Cariveau, Peter Thomas
• Application Number:
  US11/041,910
• Publication Number:
  US 20060167668A1
• Time in Patent Office: Days
• US Class Current: 703/7
• CPC Class Codes: E21B 10/00 Drill bits specially adapted for deflecting the direction of boring E21B7/064; with means for collecting substances E21B27/00

Abstract

A method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation, determining a dynamic centerline trajectory of the drill bit, and adjusting at least one design parameter based upon the graphical display of at least the dynamic centerline trajectory. To improve performance, the method can include graphically displaying the dynamic centerline trajectory and/or repeating the simulating, determining, displaying and adjusting to change a simulated performance of the fixed cutter drill bit. A drill bit design may be selected and a drill bit may be made according to the design resulting from the method of designing.

Claims

1. A method for designing a fixed cutter drill bit, comprising:

dynamically simulating the fixed cutter drill bit drilling in an earth formation for a period of time;

determining a dynamic centerline trajectory of the drill bit during the period of dynamically simulated drilling;

adjusting a value of at least one design parameter for the fixed cutter drill bit based upon at least the dynamic centerline trajectory; and

repeating the simulating, determining, and adjusting to change a simulated performance of the fixed cutter drill bit.

2. The method of claim 1, wherein repeating comprises repeating the simulating, determining and adjusting until a pre-selected performance criterion is obtained.

3. The method of claim 1, wherein adjusting the value of at least one design parameter comprises adjusting the at least one parameter to change the dynamic centerline trajectory.

4. The method of claim 1, wherein adjusting the value of the at least one design parameter comprises adjusting the at least one parameter to decrease the maximum deviation of the dynamic centerline trajectory.

5. The method of claim 1, wherein adjusting the value of the at least one design parameter comprises adjusting the at least one parameter to produce a dynamic centerline trajectory having a forward whirl.

6. The method of claim 1, wherein adjusting the value of at least one design parameter comprises adjusting the at least one parameter to eliminate a reward whirl in the dynamic centerline trajectory.

7. The method of claim 1, wherein adjusting the value of at least one design parameter comprises adjusting the at least one parameter to decrease the maximum deviation of a triangular pattern of the dynamic centerline trajectory.

8. The method of claim 1, wherein adjusting the value of at least one design parameter comprises adjusting the at least one parameter to eliminate inner looping in the dynamic centerline trajectory.

9. The method of claim 1, further comprising:

displaying the dynamic centerline trajectory of the drill bit for the period of simulated drilling time; and

the adjusting a value of at least one design parameter for the fixed cutter drill bit comprises adjusting based upon the display of the dynamic centerline trajectory.

10. The method of claim 1, wherein the drill bit design parameters comprise at least one of number of cutters, bit cutting profile, position of cutters on drill bit blades, bit axis offset of the cutter, bit diameter, cutter radius on bit, cutter vertical height on bit, cutter inclination angle on bit, cutter body shape, cutter size, cutter height, cutter diameter, cutter orientation, cutter back rake angle, cutter side rake angle, working surface shape, working surface orientation, bevel size, bevel shape, bevel orientation, cutter hardness, PDC table thickness, and cutter wear model.

11. The method of claim 1, further comprising:

adjusting a value of at least one design parameter to decrease the total imbalance force over the simulated period of drilling time.

12. The method of claim 1, further comprising:

determining radial and circumferential components of imbalance forces on the drill bit and a Beta angle between the radial and circumferential components of the imbalance forces during the period of dynamically simulated drilling; and

adjusting a value of at least one design parameter for the fixed cutter drill bit according to at least the Beta angle

13. The method of claim 1, wherein:

the simulating comprises determining a wear pattern on a plurality of cutters on the fixed cutter drill bit over the simulated drilling time based upon a constrained centerline model; and

the determining the dynamic centerline trajectory comprises using the determined wear pattern in a dynamic centerline model of the drill bit during the simulated drilling time.

14. The method of claim 1, wherein the graphically displaying comprises displaying a historical plot of at least the dynamic centerline trajectory of the drill bit graphically over the simulated period of drilling time for a plurality of increments of simulated rotation.

15. The method of claim 1, wherein a drill bit design is selected according to the adjusted at least one drill bit parameter.

16. A fixed cutter drill bit designed by the method of claim 1.

23. A fixed cutter drill bit designed by the method of claim 1.

17. A method for designing a fixed cutter drill bit, comprising:

dynamically simulating the fixed cutter drill bit drilling in an earth formation for a period of time;

determining a distance between a centerline of the fixed cutter drill bit and a theoretical centerline of a borehole drilled through an earth formation in response to an increment of simulated rotation of the fixed cutter drill bit using a mechanics analysis model, finding a plurality of the determined distances between the centerline of the fixed cutter drill bit and the theoretical centerline of a borehole for a plurality of successive increments of simulated rotation;

adjusting a value of at least one design parameter for the fixed cutter drill bit based upon at least the plurality of distances; and

repeating the simulating, determining, finding, and adjusting to change a simulated performance of the fixed cutter drill bit.

18. The method of claim 17, further comprising graphically displaying the determined distances between the centerline of the fixed cutter drill bit and the theoretical centerline of the borehole at the plurality of increments of simulated rotation of the fixed cutter drill bit.

19. The method of claim 18, wherein the repeating comprises repeating the simulating, finding, and adjusting based upon the graphically displaying until a predetermined criterion for the displayed distances is met.

20. The method of claim 19, wherein the graphically displaying comprises displaying a historical plot of the plurality of the determined distances between the centerline of the fixed cutter drill bit and a theoretical centerline of the borehole for the plurality of increments of simulated rotation.

21. The method of claim 19, wherein the graphically displaying comprises displaying a dynamic sequence of the plurality of determined distances between a centerline of the fixed cutter drill bit and a theoretical centerline of a borehole for the plurality of increments of simulated rotation over a period of time.

22. The method of claim 19 further comprising selecting a dill bit design according to the adjusted value of the at least one design parameter for the fixed cutter drill bit when predetermined criterion for the displayed distances is met.