Apparatus for weight on bit measurements, and methods of using same

• US 6,802,215 B1
• Filed: 10/15/2003
• Issued: 10/12/2004
• Est. Priority Date: 10/15/2003
• Status: Expired due to Term

• Current Assignee: GP USA Holding, LLC (NOV, Inc.)
• Original Assignee: ReedHycalog LP (NOV, Inc.)
• Inventors: Schen, Aaron, Ivie, Craig, Boucher, Marcel, Jarvis, Brian Peter
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): FITZGERALD, JOHN P
• Application Number:
  US10/605,627
• Time in Patent Office: 363 Days
• Field of Search: 731/524.8, 731/524.9, 731/525.9
• US Class Current: 73/152.48
• 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

The present invention is generally directed to a tool for obtaining weight-on-bit (WOB) measurements and methods of using such a tool. In one illustrative embodiment the tool comprises a body, at least one strain gauge cavity in the body, the strain gauge cavity having a strain gauge mounting surface that is located at a position such that a region of approximately zero axial strain due to downhole pressures during drilling operations exists on the mounting surface when the tool is subjected to downhole pressures during drilling operations, and a weight-on-bit strain gauge operatively coupled to the mounting face above the region of approximately zero axial strain. In another illustrative embodiment, the method comprises providing a weight-on-bit measurement tool comprised of a body, at least one strain gauge cavity in the body, the strain gauge cavity having a strain gauge mounting surface that is located at a position such that a region of approximately zero axial strain due to downhole pressures during drilling operations exists on the mounting surface when the tool is subjected to downhole pressures during drilling operations, and a weight-on-bit strain gauge coupled to the mounting face above the region of approximately zero axial strain. The method further comprises positioning the tool in a drill string comprised of a drill bit, drilling a well bore with the drill string, and obtaining weight-data-on-bit measurement data using the weight-on-bit strain gauge in the tool.

Claims

1. A weight-on-bit measurement tool, comprising:

a body;

at least one strain gauge cavity in said body, said strain gauge cavity having a strain gauge mounting surface that is located at a position such that a region of approximately zero axial strain due to downhole pressures during drilling operations exists on said mounting surface when said tool is subjected to said downhole pressures during drilling operations; and

a weight-on-bit strain gauge operatively coupled to said mounting face above said region of approximately zero axial strain.

2. The tool of claim 1, further comprising a cover plate positioned in an opening of said cavity.

3. The tool of claim 2, wherein said cover plate and said cavity define a chamber substantially free of liquids.

4. The tool of claim 2, wherein said cavity defines a space that is filled with a liquid.

5. The tool of claim 1, wherein said cavity has a circular cross-sectional configuration.

6. The tool of claim 1, wherein said tool is comprised of at least one of stainless steel, a carbon steel and titanium.

7. The tool of claim 1, wherein said cavity has a circular cross-sectional configuration of a diameter of approximately 1½

″ and

said mounting face is positioned at a depth of approximately 1⅛

″

below an outer surface of said body.

8. The tool of claim 1, wherein said cavity is formed in said body.

9. The tool of claim 1, wherein said cavity is defined, at least partially, by a cavity insert positioned in said body.

10. The tool of claim 9, further comprising an internal passageway formed between an internal bore of said body and said cavity insert.

11. The tool of claim 9, wherein at least a portion of said cavity insert has a conical configuration.

12. A weight-on-bit measurement tool, comprising:

a body;

at least two strain gauge cavities in said body, each of said strain gauge cavities having a strain gauge mounting surface that is located at a position such that a region of approximately zero axial strain due to downhole pressures during drilling operations exists on said mounting surface when said tool is subjected to said downhole pressures during drilling operations; and

a weight-on-bit strain gauge operatively coupled to said mounting face above said region of approximately zero axial strain.

13. The tool of claim 12, wherein said cavities are positioned on opposite sides of said tool body.

14. The tool of claim 12, further comprising a cover plate positioned in an opening of each of said cavities.

15. The tool of claim 14, wherein said cover plate and each of said cavities define a chamber substantially free of liquids.

16. The tool of claim 14, wherein each of said cavities a space that is filled with a liquid.

17. The tool of claim 12, wherein each of said cavities have a circular cross-sectional configuration.

18. The tool of claim 12, wherein said tool is comprised of at least one of stainless steel, a carbon steel and titanium.

19. The tool of claim 12, wherein each of said cavities have a circular cross-sectional configuration of a diameter of approximately 1½

″ and

said mounting face is positioned at a depth of approximately 1⅛

″

below an outer surface of said body.

20. The tool of claim 12, wherein each of said cavities are formed in said body.

21. The tool of claim 12, wherein each of said cavities are defined, at least partially, by a cavity insert positioned in said body.

22. The tool of claim 21, further comprising an internal passageway formed between an internal bore of said body and said cavity insert.

23. The tool of claim 21, wherein at least a portion of said cavity insert has a conical configuration.

24. A method, comprising:

providing a weight-on-bit measurement tool comprised of;

a body;

at least one strain gauge cavity in said body, said strain gauge cavity having a strain gauge mounting surface that is located at a position such that a region of approximately zero axial strain due to downhole pressures during drilling operations exists on said mounting surface when said tool is subjected to said downhole pressures during drilling operations; and

a weight-on-bit strain gauge operatively coupled to said mounting face above said region of approximately zero axial strain;

positioning said tool in a drill string comprised of a drill bit;

drilling a well bore with said drill string; and

obtaining weight-on-bit measurement data using said weight-on-bit strain gauge in said tool.

25. The method of claim 24, wherein said weight-on-bit measurement data is provided on a real-time basis.

26. The method of claim 24, wherein said weight-on-bit measurement data is provided on a non-real-time basis.

27. The method of claim 24, further comprising a cover plate positioned in an opening of said cavity.

28. The method of claim 27, wherein said cover plate and said cavity define a chamber substantially free of liquids.

29. The method of claim 27, wherein said cavity defines a space that is filled with a liquid.

30. The method of claim 24, wherein said cavity has a circular cross-sectional configuration.

31. The method of claim 24, wherein said tool is comprised of at least one of stainless steel, a carbon steel and titanium.

32. The method of claim 24, wherein said cavity has a circular cross-sectional configuration of a diameter of approximately 1½

″ and

said mounting face is positioned at a depth of approximately 1⅛

″

below an outer surface of said body.

33. The method of claim 24, wherein said cavity is formed in said body.

34. The method of claim 24, wherein said cavity is defined, at least partially, by a cavity insert positioned in said body.

35. The method of claim 34, further comprising an internal passageway formed between an internal bore of said body and said cavity insert.

36. The method of claim 34, wherein at least a portion of said cavity insert has a conical configuration.

37. A method, comprising:

identifying a region of approximately zero axial strain due to downhole pressures for a body to be positioned in a drill string when said body is subjected to downhole pressures during drilling operations;

providing a strain gauge cavity in said body such that a strain gauge mounting face within said cavity is located at a position wherein said region of approximately zero axial strain exists on said mounting face when said body is subjected to said downhole pressures during said drilling operations; and

coupling a weight-on-bit strain gauge to said mounting face above said region of approximately zero axial strain.

38. The method of claim 37, wherein providing a strain gauge cavity in said body comprises machining a cavity in said body.

39. The method of claim 37, wherein providing a strain gauge cavity in said body comprises forming an opening in said body and positioning a cavity insert in said opening.

40. The method of claim 37, further comprising a cover plate positioned in an opening of said cavity.

41. The method of claim 37, wherein said cover plate and said cavity define a chamber substantially free of liquids.

42. The method of claim 37, wherein said cavity defines a space that is filled with a liquid.

43. The method of claim 37, wherein said cavity has a circular cross-sectional configuration.

44. The method of claim 37, wherein said tool is comprised of at least one of stainless steel, a carbon steel and titanium.

45. The method of claim 37, wherein said cavity has a circular cross-sectional configuration of a diameter of approximately 1½

″ and

said mounting face is positioned at a depth of approximately 1⅛

″

below an outer surface of said body.

46. The method of claim 37, wherein said cavity is formed in said body.

47. The method of claim 37, wherein said cavity is defined, at least partially, by a cavity insert positioned in said body.

48. The method of claim 47, further comprising an internal passageway formed between an internal bore of said body and said cavity insert.

49. The method of claim 47, wherein at least a portion of said cavity insert has a conical configuration.