Subsurface connection methods for subsurface heaters

• US 7,860,377 B2
• Filed: 04/21/2006
• Issued: 12/28/2010
• Est. Priority Date: 04/22/2005
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Carl, Frederick Gordon Jr., Bass, Ronald Marshall, Vinegar, Harold J., Kim, Dong Sub, Keltner, Thomas Joseph, Mason, Stanley Leroy, Stegemeier, George Leo
• Primary Examiner(s): Campbell; Thor S
• Application Number:
  US11/409,559
• Publication Number:
  US 20070045267A1
• Time in Patent Office: 1,712 Days
• Field of Search: None
• US Class Current: 392/301
• CPC Class Codes: C07C 4/02 by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
• CPC Class Codes: C07C 9/04 Methane production by treatment of sewage C02F11/04; natural gas, synthetic natural gas C10L3/06
• CPC Class Codes: E21B 17/028 Electrical or electro-magnetic connections
• CPC Class Codes: E21B 36/001 Cooling arrangements
• 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 43/243 Combustion in situ
• CPC Class Codes: Y10T 29/49179 by metal fusion bonding

Abstract

A system for heating a subsurface formation is described. The system includes a first elongated heater in a first opening in the formation. The first elongated heater includes an exposed metal section in a portion of the first opening. The portion is below a layer of the formation to be heated. The exposed metal section is exposed to the formation. A second elongated heater is in a second opening in the formation. The second opening connects to the first opening at or near the portion of the first opening below the layer to be heated. At least a portion of an exposed metal section of the second elongated heater is electrically coupled to at least a portion of the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated.

Claims

1. A system for coupling heaters in a subsurface formation, comprising:

a first elongated heater in a first opening in the formation, wherein the first elongated heater includes an exposed metal section in a portion of the first opening, the portion being below a layer of the formation to be heated, and the exposed metal section being exposed to the formation;

a second elongated heater in a second opening in the formation, wherein the second opening connects to the first opening at or near the portion of the first opening below the layer to be heated; and

a container configured to be coupled to an end portion of one or more the heaters, the end portion being below the layer to be heated, the container comprising an electrical coupling material configured to facilitate, when melted and then cooled, an electrical connection between the first elongated heater and the second elongated heater.

2. The system of claim 1, wherein the electrical coupling material has a melting point below the boiling point of water at a depth of the container.

3. The system of claim 1, the system comprising in addition an initiator coupled to the container, the initiator configured to melt the electrical coupling material.

4. The system of claim 3, wherein the initiator includes a heating element that melts the electrical coupling material.

5. The system of claim 1, wherein the electrical coupling material includes a chemical mixture that chemically reacts when initiated, and the chemical reaction of the mixture produces a metal.

6. The system of claim 5, the system comprising in addition an igniter to initiate the chemical mixture reaction.

7. The system of claim 1, wherein the electrical coupling material comprises solder.

8. The system of claim 1, wherein the container is a funnel-shaped container.

9. The system of claim 1, wherein the end portion of at least one of the elongated heaters has one or more grooves and/or one or more openings configured to enhance electrical connection between the heaters and between the heaters and the electrical coupling material.

10. The system of claim 1, wherein at least one of the elongated heaters comprises an exposed metal elongated heater section having a sulfidation rate that decreases with increasing temperature of the heater, when the heater section is between 530°

C. and 650°

C.

11. The system of claim 10, wherein the exposed metal elongated heater section comprises 410 stainless steel.

12. The system of claim 10, wherein the exposed metal elongated heater section is substantially inert to galvanic corrosion.

13. The system of claim 1, wherein at least a portion of an exposed metal section of the second elongated heater is metallically bonded to at least a portion of the exposed metal section of the first elongated heater.

14. The system of claim 1, wherein at least one of the elongated heaters comprises a temperature limited heater, the temperature limited heater comprising a ferromagnetic conductor and is configured to provide, when a time varying current is applied to the temperature limited heater, and when the heater is below a selected temperature, an electrical resistance and, when the ferromagnetic conductor is at or above the selected temperature, the temperature limited heater automatically provides a reduced electrical resistance.

15. A system for coupling heaters in a subsurface formation, comprising:

a first elongated heater in a first opening in the formation, wherein the first elongated heater includes an exposed metal section in a portion of the first opening, the portion being below a layer of the formation to be heated, and the exposed metal section being exposed to the formation;

a second elongated heater in a second opening in the formation, wherein the second opening connects to the first opening at or near the portion of the first opening below the layer to be heated; and

an explosive element configured to be coupled to an end portion of at least one of the heaters, wherein the end portion below the layer to be heated, and the explosive element being configured to facilitate, when exploded, an electrical connection between the first elongated heater and the second elongated heater.

16. The system of claim 15, the system comprising in addition an initiator coupled to the explosive element, the initiator configured to initiate the explosion of the explosive element.

17. The system of claim 15, the system comprising in addition a container coupled to the end portion of at least one of the elongated heaters, the container configured to contain the explosive element such that the container contains the explosion of the explosive element.

18. The system of claim 15, wherein at least one of the elongated heaters comprises a temperature limited heater, the temperature limited heater comprising a ferromagnetic conductor and is configured to provide, when a time varying current is applied to the temperature limited heater, and when the heater is below a selected temperature, an electrical resistance and, when the ferromagnetic conductor is at or above the selected temperature, the temperature limited heater automatically provides a reduced electrical resistance.

19. A system for coupling heaters in a subsurface formation, comprising:

a first elongated heater in a first opening in the formation, wherein the first elongated heater includes an exposed metal section in a portion of the first opening, the portion being below a layer of the formation to be heated, and the exposed metal section being exposed to the formation;

at least one additional elongated heater in at least one additional opening in the formation, wherein the additional openings connect to the first opening at or near the portion of the first opening below the layer to be heated;

a container configured to be coupled to an end portion of at least one of the heaters, the end portion being below the layer to be heated, the container comprising one or more openings for at least one of the additional elongated heaters to be inserted into the container; and

one or more explosive elements configured to be coupled to the container, the explosive elements being configured to facilitate, when exploded, an electrical connection between the first elongated heater and at least one of the additional elongated heaters.

20. The system of claim 19, the system comprising in addition a battery, the battery configured to provide power to the explosive elements.

21. The system of claim 19, the system comprising in addition one or more triggers in the openings, the triggers configured to trigger the explosion of the explosive elements after at least one of the additional elongated heaters is placed in at least one opening.

22. The system of claim 19, wherein the explosive elements are configured to crimp together the elongated heaters such that the elongated heaters are electrically coupled.

23. The system of claim 19, wherein the container is a funnel-shaped container.

24. The system of claim 19, wherein the end portion of at least one of the elongated heaters has one or more grooves and/or one or more openings configured to enhance electrical connection between the heaters and between the heaters and the electrical coupling material.

25. The system of claim 19, wherein at least one elongated heater comprises an exposed metal elongated heater section having a sulfidation rate that decreases with increasing temperature of the heater, when the heater section is between 530°

C. and 650°

C.

26. The system of claim 25, wherein the exposed metal elongated heater section comprises 410 stainless steel.

27. The system of claim 25, wherein the exposed metal elongated heater section is substantially inert to galvanic corrosion.

28. The system of claim 19, wherein an exposed metal section of at least one of the additional heaters is metallically bonded to at least a portion of the exposed metal section of the first elongated heater.

29. The system of claim 19, wherein at least one of the elongated heaters comprises a temperature limited heater, the temperature limited heater comprising a ferromagnetic conductor and is configured to provide, when a time varying current is applied to the temperature limited heater, and when the heater is below a selected temperature, an electrical resistance and, when the ferromagnetic conductor is at or above the selected temperature, the temperature limited heater automatically provides a reduced electrical resistance.

30. A method for coupling heaters in a subsurface formation, comprising:

placing a first elongated heater in the first opening in the formation, wherein the first elongated heater includes an exposed metal section in a portion of the first opening, the portion being below a layer of the formation to be heated, and the exposed metal section being exposed to the formation;

placing the second elongated heater in the second opening in the formation, wherein the second opening connects to the first opening at or near the portion of the first opening below the layer to be heated; and

coupling an exposed metal section of the second elongated heater to the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated such that the exposed metal section of the first elongated heater is electrically coupled to the exposed metal section of the second elongated heater.

31. The method of claim 30, further comprising coupling the exposed metal section of the second elongated heater to the exposed metal section of the first elongated heater by:

placing an end portion of the exposed metal section of the second elongated heater in a container coupled to an end portion of the exposed metal section of the first elongated heater;

melting a metal in the container; and

allowing the metal in the container to cool to create an electrical connection between the first elongated heater and the second elongated heater.

32. The method of claim 31, further comprising melting the electrical coupling material at a temperature below the boiling point of water at a depth of the container.

33. The method of claim 31, further comprising displacing water in the container by melting the electrical coupling material.

34. The method of claim 31, further comprising using an initiator to melt the electrical coupling material.

35. The method of claim 31, further comprising using a heating element to melt the electrical coupling material.

36. The method of claim 31, further comprising initiating a chemical reaction of a chemical mixture to produce the electrical coupling material.

37. The method of claim 30, further comprising coupling the exposed metal section of the second elongated heater to the exposed metal section of the first elongated heater by:

coupling an explosive element to an end portion of the exposed metal section of the first elongated heater;

placing an end portion of the exposed metal section of the second elongated heater near the explosive element; and

exploding the explosive element to create an electrical connection between the first elongated heater and the second elongated heater.

38. The method of claim 30, further comprising coupling the exposed metal section of the second elongated heater to the exposed metal section of the first elongated heater by:

placing an end portion of the exposed metal section of the second elongated heater in an opening in a container coupled to the exposed metal section of the first elongated heater; and

exploding one or more explosive elements coupled to the container to create an electrical connection between the first elongated heater and the second elongated heater.

39. The method of claim 30, wherein the exposed metal section of the first elongated heater is electrically coupled to the exposed metal section of the second elongated heater below a water level in the formation.

40. The method of claim 30, wherein the exposed metal section of the first elongated heater is metallically bonded to the exposed metal section of the second elongated heater below a water level in the formation.