STATORS FOR DOWNWHOLE MOTORS, METHODS FOR FABRICATING THE SAME, AND DOWNHOLE MOTORS INCORPORATING THE SAME

• US 20110116959A1
• Filed: 11/13/2009
• Published: 05/19/2011
• Est. Priority Date: 11/13/2009
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Sindt, Olivier, Ramier, Julien, Akbari, Hossein
• Granted Patent: US 8,777,598 B2
• Time in Patent Office: Days
• US Class Current: 418/48
• CPC Class Codes: B29C 70/745 Filling cavities in the preformed part for joining B29C70/84
• CPC Class Codes: B29K 2101/10 Thermosetting resins
• CPC Class Codes: B29K 2101/12 Thermoplastic materials
• CPC Class Codes: B29K 2905/08 Transition metals
• CPC Class Codes: B29L 2023/22 Tubes or pipes, i.e. rigid bent tubes not for use as pipe couplings B29L2023/004
• CPC Class Codes: E21B 4/02 Fluid rotary type drives
• CPC Class Codes: F04C 13/008 Pumps for submersible use, i.e. down-hole pumping
• CPC Class Codes: F04C 2/107 with helical teeth
• CPC Class Codes: F04C 2/1071 the inner and outer member having a different number of threads and one of the two being made of elastic materials, e.g. Moineau type
• CPC Class Codes: F04C 2/1075 Construction of the stationary member
• CPC Class Codes: F04C 2230/21 by casting
• CPC Class Codes: F05C 2201/0475 Copper or alloys thereof
• CPC Class Codes: F05C 2225/00 Synthetic polymers, e.g. plastics; Rubber
• CPC Class Codes: F05C 2225/02 Rubber
• CPC Class Codes: F05C 2225/10 Polyimides, e.g. Aurum
• CPC Class Codes: F05C 2225/12 Polyetheretherketones, e.g. PEEK
• CPC Class Codes: F05C 2253/12 Coating
• CPC Class Codes: F05C 2253/18 Filler
• CPC Class Codes: F05C 2253/22 Reinforcements
• CPC Class Codes: Y10T 29/4932 Turbomachine making

Abstract

The present invention recites a method of fabricating a stator for a downhole motor, the method comprising the steps of providing a stator tube having an interior surface and applying a bonding agent to the interior surface of the stator tube. Additionally, a mandrel is positioned within the stator tube, the mandrel having an outer geometry that is complimentary to a desired inner geometry for the stator. Furthermore, a reinforcing material is introduced into the stator tube to fill space between the mandrel and the interior surface of the stator tube and subsequently solidified to bond the reinforcing material to the interior surface of the stator tube, The mandrel is then removed from the bonded stator tube and reinforcing material such that a stator is fabricated.

Claims

1. A method of fabricating a stator for a downhole motor, the method comprising:

providing a stator tube having an interior surface;

applying a bonding agent to the interior surface of the stator tube;

positioning a mandrel within the stator tube, the mandrel having an outer geometry that is complimentary to a desired inner geometry for the stator;

introducing a reinforcing material into the stator tube to fill space between the mandrel and the interior surface of the stator tube;

solidifying the reinforcing material to bond the reinforcing material to the interior surface of the stator tube; and

removing the mandrel from the bonded stator tube and reinforcing material;

thereby fabricating the stator.

2. The method of claim 1, wherein the stator tube comprises a material selected from the group consisting of:

iron, steel, high speed steel, carbon steel, tungsten steel, brass, and copper.

3. The method of claim 1, wherein the bonding agent is a single-layer bonding agent.

4. The method of claim 1, wherein the bonding agent is a multiple-layer bonding agent.

5. The method of claim 1, wherein the mandrel comprises a material selected from the group consisting of:

iron, steel, high speed steel, carbon steel, tungsten steel, brass, and copper.

6. The method of claim 1, wherein the mandrel is coated with a release agent.

7. The method of claim 1, wherein the reinforcing material is a composite.

8. The method of claim 1, wherein the reinforcing material is a polymer.

9. The method of claim 8, wherein the reinforcing material is a thermosetting plastic.

10. The method of claim 8, wherein the reinforcing material is a thermoplastic.

11. The method of claim 8, wherein the reinforcing material comprises one or more selected from the group consisting of:

epoxy resins, polyimides, polyketones, polyetheretherketones (PEEK), phenolic resins, and polyphenylene sulfides (PPS).

12. The method of claim 1, wherein the reinforcing material is in a form selected from the group consisting of:

a liquid, a paste, a slurry, a power, and granular.

13. The method of claim 1, wherein the reinforcing material is cross-linked.

14. The method of claim 1, wherein the reinforcing material has a high degree of crystallinity.

15. The method of claim 1, wherein the step of solidifying the reinforcing material to bond the reinforcing material to the interior surface of the stator tube further comprises one or techniques selected from the group consisting of:

heat curing, radiation curing, steam curing, and cooling.

16. A stator for a downhole motor, the stator comprising:

a stator tube including an inner surface; and

a solidified reinforcing material bonded to the inner surface, the solidified reinforcing material having an inner surface defining an internal helical cavity including a plurality of internal lobes.

17. A downhole motor comprising:

a stator comprising;

a stator tube including an inner surface; and

a solidified reinforcing material bonded to the inner surface, the solidified reinforcing material having an inner surface defining an internal helical cavity including a plurality of internal lobes; and

a rotor received within the stator.

18. The downhole motor of claim 17, wherein the rotor is coated with an elastomer.

19. The downhole motor of claim 18, wherein the elastomer comprises one or more selected from the group consisting of:

rubber, natural rubber (NR), synthetic polyisoprene (IR), butyl rubber, halogenated butyl rubber, polybutadiene (BR), nitrile rubber, nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), carboxylated hydrogenated nitrile butadiene rubber (XHNBR), chloroprene rubber (CR) Fluorocarbon rubber (FKM), and Perfluoroelastomers (FFKM)