Magnetorheological fluid apparatus, especially adapted for use in a steerable drill string, and a method of using same

• US 6,257,356 B1
• Filed: 10/06/1999
• Issued: 07/10/2001
• Est. Priority Date: 10/06/1999
• Status: Expired due to Term

• Current Assignee: APS Technology Inc
• Original Assignee: APS Technology Inc
• Inventors: Wassell, Mark Ellsworth
• Primary Examiner(s): DANG, HOANG C
• Application Number:
  US09/413,111
• Time in Patent Office: 643 Days
• Field of Search: 175/73, 175/61, 166/66.5, 166/66.6
• US Class Current: 175/61
• CPC Class Codes: E21B 7/06 Deflecting the direction of boreholes

Abstract

A rotatable steerable drill string in which guidance module controls the direction of the drilling. A magnetorheological fluid in the module supplies pressure to pistons that apply forces to the wall of the bore and thereby alter the direction of the drilling. The pressure applied by the magnetorheological fluid is regulated by valves that apply a magnetic field to the fluid so as to increase or decrease its fluid shear strength thereby controlling the actuation of the pistons and the direction of the drilling.

Claims

1. A guidance apparatus for steering a rotatable drill string through a bore hole, comprising:

a) a housing for incorporation into said drill string;

b) a movable member mounted in said housing so as to be capable of extending and retracting in the radial direction, said movable member having a distal end projecting from said housing adapted to engage the walls of said bore hole;

c) a supply of a magnetorheological fluid;

d) means for pressurizing said magnetorheological fluid;

e) means for supplying said pressurized rheological fluid to said movable member, the pressure of said rheological fluid generating a force urging said movable member to extend radially outward, the magnitude of said force being proportional to the pressure of said rheological fluid supplied to said movable member; and

f) a valve for regulating the pressure of said magnetorheological fluid supplied to said movable member so as to alter said force urging said movable member radially outward, said valve comprising means for subjecting said magnetorheological fluid to a magnetic field so as to change the shear strength thereof.

2. The guidance apparatus according to claim 1, wherein said movable member is a piston slidably mounted in said housing.

3. The guidance apparatus according to claim 1, wherein said means for supplying said pressurized fluid comprises a passage placing said pressurizing means in fluid flow communication with said movable member, and wherein said valve is disposed in said passage.

4. The guidance apparatus according to claim 1, further comprising:

g) a second movable member mounted in said housing so as to be capable of extending and retracting in the radial direction, said second movable member having a distal end projecting from said housing that is adapted to engage the walls of said bore hole, said second movable member being circumferentially spaced from said first movable member;

h) means for supplying said pressurized rheological fluid to said second movable member; and

i) a second valve for regulating the pressure of said magnetorheological fluid supplied to said second movable member so as to alter said force urging said second movable member radially outward, said second valve comprising means for subjecting said magnetorheological fluid to a magnetic field so as to change the shear strength thereof.

5. The guidance apparatus according to claim 1, further comprising means for biasing said movable member radially inward.

6. The guidance apparatus according to claim 1, wherein said magnetorheological fluid comprises a suspension of magnetic particles.

7. The guidance apparatus according to claim 1, further comprising a controller for controlling a flow of electrical current to said valve, and wherein said valve comprises windings through which said electrical current flows for creating said magnetic field.

8. The guidance apparatus according to claim 1, wherein said means for supplying said pressurized fluid comprises a passage placing said pressurizing means in fluid flow communication with said movable member, and wherein said valve is a first valve, said first valve disposed in said passage upstream of said movable member, and further comprising a second valve for regulating the pressure of said magnetorheological fluid supplied to said movable member so as to also alter said force urging said movable member radially outward, said second valve comprising means for subjecting said magnetorheological fluid to a magnetic field so as to change the shear strength thereof, said second valve disposed in said passage downstream of said movable member.

9. The guidance apparatus according to claim 1, further comprising:

g) means for receiving a steering instruction from a location proximate the surface of the earth; and

h) a controller for generating a flow of electrical current for operating said valve in response to said steering instruction received.

10. The guidance apparatus according to claim 9, wherein said steering instruction comprises a direction to which said rotatable drill string is to be steered.

11. The guidance apparatus according to claim 9, wherein said steering instruction comprises an instruction representative of the amplitude of said flow of electrical current.

12. The guidance apparatus according to claim 9, wherein said steering instruction receiving means comprises a pressure pulsation sensor.

13. The guidance apparatus according to claim 1, further comprising means for determining the angular orientation of said movable member.

14. The guidance apparatus according to claim 1, wherein said movable member is first movable member, and further comprising a second movable member mounted in said housing so as to be capable of extending and retracting in the radial direction, said second movable member having a distal end projecting from said housing adapted to engage the walls of said bore hole and being circumferentially displaced from said first movable member.

15. A guidance apparatus for steering a drill string drilling a bore hole having a wall, comprising:

a) a housing for incorporation into said drill string;

b) a pressurized magnetorheological fluid disposed within said housing;

c) a movable member mounted in said housing so as to be capable of movement in response to said pressure of said magnetorheological fluid, said movable member having a distal end projecting from said housing adapted to engage said wall of said bore hole;

d) an electromagnet located so as to create a magnetic field that alters the shear strength of at least a portion of said magnetorheological fluid; and

e) a controller for controlling the flow of electrical current to said electromagnet so as to control said pressure of at least said portion of said rheological fluid.

16. The guidance apparatus according to claim 15, wherein said movable member is a first movable member and said electromagnet is a first electromagnet, and further comprising:

f) a second movable member mounted in said housing so as to be capable of movement in response to said pressure of said magnetorheological fluid, said second movable member having a distal end projecting from said housing adapted to engage said wall of said bore hole and being circumferentially displaced from said first movable member;

g) a second electromagnet located so as to create a second magnetic field that alters the shear strength of a second portion of said magnetorheological fluid.

17. The guidance apparatus according to claim 15, further comprising means for receiving a steering instruction from a location proximate the surface of the earth, and wherein said controller controls the flow of electrical current to said electromagnet in response to said steering instructions received.

18. The guidance apparatus according to claim 17, wherein said steering instruction comprises a direction to which said drill string is to be steered.

19. The guidance apparatus according to claim 15, wherein said steering instruction comprises an instruction representative of the amplitude of said flow of electrical current to said electromagnet.

20. The guidance apparatus according to claim 15, wherein said bore hole is filled with drilling fluid, and further comprising a pressure transducer for sensing pressure pulsations in said drilling fluid that contain information representative of a steering instruction.

21. A guidance apparatus for steering a drill string while drilling a bore hole having a wall, comprising:

a) means for applying a force to said wall of said bore hole in response to pressure from a magnetorheological fluid so as to direct the path of said drill string;

b) an electromagnet located so as to create a magnetic field that alters the shear strength of at least a portion of said magnetorheological fluid; and

c) a controller for controlling a flow of electrical current to said electromagnet so as to control the strength of said magnetic field to which at least said portion of said rheological fluid is subjected.

22. The apparatus according to claim 21, further comprising means for receiving a steering instruction from a location proximate the surface of the earth, and wherein said controller controls the flow of electrical current to said electromagnet in response to said steering instructions received.

23. The guidance apparatus according to claim 22, wherein said steering instruction comprises a direction to which said device is to be steered.

24. The guidance apparatus according to claim 22, wherein said steering instruction comprises an instruction representative of the amplitude of said flow of electrical current to said electromagnet.

25. The guidance apparatus according to claim 21, wherein said bore hole is filled with drilling fluid, and further comprising a pressure transducer for sensing pressure pulsations in said drilling fluid that contain information representative of a steering instruction.

26. An apparatus for use down hole in a well, comprising:

a) a housing;

b) a magnetorheological fluid disposed within said housing;

c) an electromagnet located so as to create a magnetic field that alters the shear strength of at least a portion of said magnetorheological fluid; and

d) a controller for controlling a flow of electrical current to said electromagnet so as to control the strength of said magnetic field to which said portion of said rheological fluid is subjected.

27. The apparatus according to claim 26, further comprising means for receiving information from a location proximate the surface of the earth for controlling said flow of electrical current to said electromagnet.

28. The guidance apparatus according to claim 26, wherein said well is filled with a fluid, and further comprising a pressure transducer for sensing pressure pulsations in said well fluid that contain information for controlling said flow of electrical current to said electromagnet.

29. A method of steering a drill string drilling a bore hole, said drill string having a guidance apparatus comprising at least one movable member mounted therein so that movement of said movable member alters the path of said drilling, comprising the steps of:

a) supplying a magnetorheological fluid to said movable member;

b) creating a magnetic field to which said magnetorheological fluid is subjected that affects the pressure of said magnetorheological fluid supplied to said movable member, thereby causing said movable member to move so as to alter the path of said drill string.

30. The steering method according to claim 29, further comprising the step of varying the strength of said magnetic field so as to vary the pressure of said magnetorheological fluid supplied to said movable member, thereby further altering the direction of the path of said drill string.

31. The steering method according to claim 29, further comprising the step of transmitting a steering instruction to said guidance device from a location proximate the surface of the earth.

32. The steering method according to claim 31, wherein said bore hole is filled with drilling fluid, and wherein said step of transmitting said steering instruction comprising transmitting information representative of a steering instruction through said drilling fluid.

33. The steering method according to claim 32, wherein the step of transmitting said information through said drilling fluid comprises transmitting pressure pulsations through said drilling fluid to a pressure transducer.

34. The steering method according to claim 29, wherein movement of said movable member causes said movable member to apply a force to said bore hole that alters the path of said drill string.

35. A method of steering a drill string drilling a bore hole having a wall, said drill string having a guidance apparatus comprising a plurality of movable members mounted therein each of which is adapted to apply a force to said bore hole wall that alters the path of said drill string, comprising the steps of:

a) supplying magnetorheological fluid to each of said movable members;

b) subjecting said magnetorheological fluid supplied to at least a selected one of said movable members to a magnetic field.

36. The steering method according to claim 35, further comprising the step of selectively varying the strength of a magnetic field to which said magnetorheological fluid supplied to each of said movable members is subjected so as to vary the force applied by said movable members to said bore hole wall.

37. The steering method according to claim 35, further comprising the step of transmitting a steering instruction to said guidance device from a location proximate the surface of the earth.

38. The steering method according to claim 37, wherein said bore hole is filled with drilling fluid, and wherein said step of transmitting said steering instruction comprising transmitting information representative of a steering instruction through said drilling fluid.

39. The steering method according to claim 38, wherein the step of transmitting said information through said drilling fluid comprises transmitting pressure pulsations through said drilling fluid to a pressure transducer.

40. A method for operating an apparatus down in a well, comprising the steps of:

a) flowing a magnetorheological fluid through at least a portion of said apparatus;

b) subjecting at least a portion of said magnetorheological fluid to a magnetic field so as to alter the shear strength thereof.