Downhole Electric Power Generator

• US 20080047753A1
• Filed: 08/24/2006
• Published: 02/28/2008
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Hall, David R., Dahlgren, Scott, Comfoltey, Michael
• Granted Patent: US 8,033,328 B2
• Time in Patent Office: Days
• US Class Current: 175/57
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes
• CPC Class Codes: F16C 2352/00 Apparatus for drilling
• CPC Class Codes: F16C 2361/55 Flywheel systems
• CPC Class Codes: F16C 32/0436 with a conductor on one part movable with respect to a magnetic field, e.g. a body of copper on one part and a permanent magnet on the other part
• CPC Class Codes: F16C 39/06 using magnetic means

Abstract

A downhole electric power generator is disclosed in one embodiment of the invention as including an inlet channel formed in a bore of a downhole tool string component for conveying a moving downhole fluid and a turbine coupled to the inlet channel to receive the downhole fluid. The turbine converts the energy of the moving downhole fluid into rotational energy where it is stored using a flywheel. The flywheel may then be coupled to an electrical generator to convert the rotational energy to electrical energy. In certain embodiments, a continuously variable transmission may be inserted between the turbine and the flywheel. The entire generator may, in certain embodiments, be designed small enough to reside in the wall of a downhole tool.

Claims

1. A downhole generator comprising:

an inlet channel formed in a bore of a downhole tool string component for conveying a moving downhole fluid;

a turbine coupled to the inlet channel to receive the downhole fluid and convert the energy thereof into rotational energy;

a flywheel operably coupled to the turbine to store the rotational energy; and

an electrical generator operably coupled to the flywheel to convert the rotational energy to electrical energy.

2. The downhole generator of claim 1, further comprising magnetic bearings to support the load of the flywheel during rotation.

3. The downhole generator of claim 1, wherein the magnetic bearings comprise a Halbach array of magnets.

4. The downhole generator of claim 1, further comprising an outlet channel to vent the downhole fluid away from the turbine.

5. The downhole generator of claim 4, wherein the outlet channel is vented into the central bore of a downhole tool.

6. The downhole generator of claim 4, wherein the outlet channel is vented into an annulus between a downhole tool and a borehole wall.

7. The downhole generator of claim 1, further comprising a valve to regulate the flow of the downhole fluid through the inlet channel.

8. The downhole generator of claim 1, further comprising a continuously variable transmission operably connecting the turbine to the flywheel.

9. The downhole generator of claim 1, wherein the downhole generator is located in the wall of a downhole tool.

10. The downhole generator of claim 1, further comprising a vacuum chamber enclosing at least one of the flywheel and the generator.

11. A method for generating electricity in a downhole environment, the method comprising:

receiving a moving downhole fluid;

converting energy of the downhole fluid to rotational energy;

storing the rotational energy; and

converting the rotational energy to electrical energy.

12. The method of claim 11, wherein storing comprises storing the rotational energy with a rotating flywheel.

13. The method of claim 12, further comprising magnetically levitating the rotating flywheel

14. The method of claim 13, wherein magnetically levitating comprises levitating the flywheel using a Halbach array of magnets.

15. The method of claim 11, further comprising venting the downhole fluid after converting the energy thereof to rotational energy.

16. The method of claim 15, wherein venting comprises expelling the downhole fluid into the central bore of a downhole tool.

17. The method of claim 15, wherein venting comprises expelling the downhole fluid into an annulus between a downhole tool and a borehole wall.

18. The method of claim 11, further comprising regulating the flow of the downhole fluid.

19. An apparatus for generating electricity in a downhole environment, the apparatus comprising:

a downhole tool; and

a downhole generator installed in the downhole tool to provide a source of electrical power, the downhole generator comprising;

a turbine to receive a moving downhole fluid and convert the energy thereof into rotational energy;

a flywheel operably coupled to the turbine to store the rotational energy; and

an electrical generator operably coupled to the flywheel to convert the rotational energy to electrical energy.

20. The apparatus of claim 19, wherein the downhole generator is located in the wall of the downhole tool.