System and apparatus for modeling the behavior of a drilling assembly

• US 8,775,145 B2
• Filed: 02/09/2012
• Issued: 07/08/2014
• Est. Priority Date: 02/11/2011
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Downton, Geoffrey C.
• Primary Examiner(s): Thangavelu, Kandasamy
• Application Number:
  US13/370,013
• Publication Number:
  US 20120292110A1
• Time in Patent Office: 880 Days
• Field of Search: 703/10, 175/24, 175/57, 175/27, 175/61, 175/40, 175/50, 175/325.2
• US Class Current: 703/10
• 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
• CPC Class Codes: E21B 47/022 of the borehole, e.g. using geomagnetism
• CPC Class Codes: E21B 7/04 Directional drilling

Abstract

A method for drilling a borehole includes obtaining, while drilling the borehole, sensor data for the drilling assembly, analyzing, while drilling the borehole, the sensor data using a drilling behavior model to obtain results, and adjusting the drilling of the borehole based on the results. The drilling behavior model models drilling of the borehole using a distance drilled, a number of touch points, a number of bend angles, a number of external moments, a number of lengths of distributed weights, a lateral displacement of a center of the borehole at a bit, at least one vertical displacement from the center of the borehole, at least one angular offset, at least one force, and at least one mass per unit length.

Claims

1. A method for drilling a borehole, comprising:

obtaining, while drilling the borehole, sensor data for the drilling assembly;

analyzing, while drilling the borehole, the sensor data using a drilling behavior model to obtain results,

wherein the drilling behavior model models drilling of the borehole using a distance drilled, a number of touch points, a number of bend angles, a number of external moments, a number of lengths of distributed weights, a lateral displacement of a center of the borehole at a bit, at least one vertical displacement from the center of the borehole, at least one angular offset, at least one force, and at least one mass per unit length; and

adjusting the drilling of the borehole based on the results.

2. The method of claim 1, wherein the drilling behavior model comprises an equation expressible as:

3. The method of claim 2, wherein the drilling behavior model is expressed using a Laplace transformation and each coefficient is set as a constant.

4. The method of claim 1, wherein the drilling behavior model comprises an equation expressible as:

5. The method of claim 4, wherein the results of analyzing H(s) specify a stability level of the borehole.

6. The method of claim 1, wherein the drilling behavior model predicts at least one selected from a group consisting of a lateral displacement, an angular orientation, and a curvature of the borehole at a predefined point.

7. The method of claim 1, wherein the drilling behavior model identifies a failure of the borehole based on at least one coefficient of the drilling behavior model exceeding a predefined threshold.

8. The method of claim 1, wherein the drilling behavior model models the drilling of the borehole when a working actuator is used to compensate for a failed actuator.

9. The method of claim 1, wherein the drilling behavior model is executed downhole within a downhole steering tool, and the drilling is adjusted by the downhole steering tool.

10. The method of claim 9, wherein adjusting the drilling of the borehole comprises:

modifying, while the drilling assembly is located downhole, a position of at least one stabilizer on the drilling assembly in response to the results.

11. The method of claim 9, wherein adjusting the drilling of the borehole comprises:

modifying, while the drilling assembly is located downhole, a diameter of at least one stabilizer on the drilling assembly in response to the results.

12. The method of claim 9, wherein adjusting the drilling of the borehole comprises:

modifying, while the drilling assembly is located downhole, a bit in response to the results, wherein modifying the bit comprises modifying at least one selected from a group consisting of a shape of a gauge of the bit and a position of a cutter on the bit, and a position of snubbers on the bit.

13. The method of claim 9, wherein adjusting the drilling of the borehole comprises:

modifying, while the drilling assembly is located downhole, at least one selected from a group consisting of a lateral force and position of at least one actuator in response to the results.

14. The method of claim 9, wherein adjusting the drilling of the borehole comprises:

modifying, while the drilling assembly is located downhole, a bottom hole assembly on the drilling assembly in response to the results by performing at least one selected from a group consisting of modifying a weight of the bottom hole assembly and a cross section of a tubular in the bottom hole assembly.

15. The method of claim 1, further comprising:

analyzing the results to identify a shape of the hole.

16. The method of claim 1, wherein the model models behavior of a downhole assembly lacking any subsurface steering element.

17. The method of claim 1, further comprising:

creating an orthogonal model to analyze the drilling in three dimensions.

18. The method of claim 1, wherein the drilling behavior model models drilling using a drilling assembly comprising a hole opener and a bit.

19. The method of claim 1, further comprising:

obtaining, while drilling the borehole, initial sensor data for the drilling assembly;

analyzing, to obtain initial results, the initial sensor data using the drilling behavior model;

obtaining an actual drilling behavior of the drilling assembly;

comparing the initial results and the actual drilling behavior to identify a discrepancy; and

refining, in response to identifying the discrepancy, at least one coefficient of the drilling behavior model.

20. A method for generating a drilling behavior model, the method comprising:

obtaining, while drilling the borehole, initial sensor data for the drilling assembly;

generating, while drilling the borehole, a partial set of coefficients using the initial sensor data;

obtaining, while drilling the borehole, an actual drilling behavior of the drilling assembly;

computing, while drilling the borehole and using the partial set of coefficients in the drilling behavior model and the actual drilling behavior, a remaining set of coefficients to create a complete set of coefficients,

wherein the drilling behavior model models drilling of the borehole using a distance drilled, a number of touch points, a number of bend angles, a number of external moments, a number of lengths of distributed weights, a lateral displacement of a center of the borehole at a bit, at least one vertical displacement from the center of the borehole, at least one angular offset, at least one force, and at least one mass per unit length; and

storing, the complete set of coefficients, wherein the complete set of coefficients are used in the drilling behavior model to manage the drilling of the borehole.

21. The method of claim 20, wherein the drilling behavior model comprises an equation expressible as:

22. The method of claim 20, wherein the drilling behavior model comprises an equation expressible as:

23. The method of claim 20, further comprising:

obtaining, while drilling the borehole, new sensor data for the drilling assembly;

analyzing, to obtain results, the new sensor data using the drilling behavior model and the complete set of coefficients; and

adjusting the drilling of the borehole based on the results.

24. A system for drilling a borehole, comprising:

a data repository for storing sensor data and a plurality of coefficients;

a model execution hardware for executing a model engine, the model engine comprising instructions for;

obtaining, while drilling the borehole, sensor data for the drilling assembly;

analyzing, while drilling the borehole, the sensor data using a drilling behavior model to obtain results,

wherein the drilling behavior model models drilling of the borehole using a distance drilled, a number of touch points, a number of bend angles, a number of external moments, a number of lengths of distributed weights, a lateral displacement of a center of the borehole at a bit, at least one vertical displacement from the center of the borehole, at least one angular offset, at least one force, and at least one mass per unit length; and

adjusting the drilling of the borehole based on the results.

25. The system of claim 24, wherein the drilling behavior model comprises an equation expressible as:

26. The system of claim 24, wherein the drilling behavior model comprises an equation expressible as:

27. The system of claim 24, further comprising:

a plurality of sensors for gathering the sensor data; and

drilling assembly equipment configured to;

receive the command from the model execution hardware; and

self-adjust based on the command.

28. The system of claim 24, wherein the model execution hardware is a downhole steering tool.

29. The system of claim 28, wherein the downhole steering tool comprises a well plan and adjusts the drilling of the borehole based on the well plan and the results.

30. The system of claim 29, wherein the downhole steering tool is configured to obtain a set of objectives and generate the well plan.

31. The system of claim 24, wherein the data repository comprises a plurality of versions of the drilling behavior model.