Methods for forming long subsurface heaters

• US 8,536,497 B2
• Filed: 10/13/2008
• Issued: 09/17/2013
• Est. Priority Date: 10/19/2007
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Kim, Dong Sub
• Primary Examiner(s): FUQUA, SHAWNTINA T
• Application Number:
  US12/250,346
• Publication Number:
  US 20090194524A1
• Time in Patent Office: 1,800 Days
• Field of Search: 219/544, 219541- 2, 219/546, 219/548, 296/11
• US Class Current: 219/544
• CPC Class Codes: E21B 36/04 using electrical heaters
• CPC Class Codes: E21B 43/24 using heat, e.g. steam injection
• CPC Class Codes: E21B 43/30 Specific pattern of wells, e.g. optimising the spacing of wells
• CPC Class Codes: H01F 27/38 Auxiliary core members; Auxiliary coils or windings
• CPC Class Codes: H01F 29/04 having provision for tap-changing without interrupting the load current
• CPC Class Codes: H01J 37/32926 Software, data control or modelling
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: Y10T 29/49083 Heater type

Abstract

A method for forming a longitudinal subsurface heater includes longitudinally welding an electrically conductive sheath of an insulated conductor heater along at least one longitudinal strip of metal. The longitudinal strip is formed into a tubular around the insulated conductor heater with the insulated conductor heater welded along the inside surface of the tubular.

Claims

1. A method for forming a longitudinal subsurface heater, comprising:

longitudinally welding an electrically conductive sheath of an insulated conductor heater along at least one longitudinal strip of metal; and

forming the longitudinal strip into a tubular around the insulated conductor heater with the insulated conductor heater welded along the inside surface of the tubular.

2. The method of claim 1, wherein forming the longitudinal strip of metal into the tubular comprises rolling the strip of metal into the tubular.

3. The method of claim 1, further comprising electrically shorting a distal end of the tubular to a distal end of the sheath and a center conductor of the insulated conductor heater.

4. The method of claim 1, further comprising forming the tubular by welding the longitudinal lengths of the strip of metal together.

5. The method of claim 1, further comprising forming the tubular by welding the longitudinal lengths of the strip of metal together at a circumferential location away from the point of contact between the tubular and the insulated conductor heater.

6. The method of claim 1, wherein the tubular is formed from a plurality of longitudinal strips of metal.

7. The method of claim 1, wherein the insulated conductor heater comprises a center conductor at least partially surrounded by an electrical insulator, and the sheath at least partially surrounding the electrical insulator.

8. A method for forming a longitudinal subsurface heater, comprising:

longitudinally welding an electrically conductive sheath of an insulated conductor heater along an inside surface of a metal tubular.

9. The method of claim 8, wherein the tubular is formed from one or more longitudinal strips of metal.

10. The method of claim 8, further comprising electrically shorting a distal end of the tubular to a distal end of the sheath and a center conductor of the insulated conductor heater.

11. The method of claim 8, wherein the insulated conductor heater comprises a center conductor at least partially surrounded by an electrical insulator, and the electrically conductive sheath at least partially surrounding the electrical insulator.

12. A longitudinal subsurface heater, comprising:

an insulated conductor heater, comprising;

an electrical conductor;

an electrical insulator at least partially surrounding the electrical conductor; and

an electrically conductive sheath at least partially surrounding the electrical insulator;

a metal tubular at least partially surrounding the insulated conductor heater; and

wherein the sheath of the insulated conductor heater is longitudinally welded along an inside surface of the metal tubular.

13. The heater of claim 12, wherein a distal end of the tubular is electrically shorted to a distal end of the sheath and the electrical conductor of the insulated conductor heater.

14. The heater of claim 12, wherein the tubular is formed from one or more longitudinal strips of metal.

15. The heater of claim 12, wherein the tubular has been formed by welding longitudinal lengths of a strip of metal together.

16. The heater of claim 12, wherein the tubular is configured to allow fluids to flow through the tubular.

17. The heater of claim 12, wherein the metal tubular is ferromagnetic.

18. The heater of claim 12, wherein the electrical conductor comprises copper.

19. The heater of claim 12, wherein the electrical insulator comprises magnesium oxide.

20. The heater of claim 12, wherein the metal tubular is non-ferromagnetic, and the metal tubular is coated with thin electrically insulating coating.

21. The heater of claim 12, wherein the heater is a temperature limited heater.

22. A method for treating a subsurface formation using an electric heater, comprising:

providing the electric heater to an opening in the subsurface formation, the electric heater comprising;

an insulated conductor heater, comprising;

an electrical conductor;

an electrical insulator at least partially surrounding the electrical conductor; and

an electrically conductive sheath at least partially surrounding the electrical insulator;

a metal tubular at least partially surrounding the insulated conductor heater;

wherein the sheath of the insulated conductor heater is longitudinally welded along an inside surface of the metal tubular; and

heating the subsurface formation by providing electrical current to the electric heater.

23. The method of claim 22, further comprising providing at least one heat transfer fluid to the tubular.

24. The method of claim 22, further comprising heating the subsurface formation by providing time-varying electrical current to the electric heater.