Induction heaters used to heat subsurface formations

• US 8,162,059 B2
• Filed: 10/13/2008
• Issued: 04/24/2012
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Salamander IP Holdings LLC
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Nguyen, Scott Vinh, Bass, Ronald M.
• Primary Examiner(s): Kreck, John
• Application Number:
  US12/250,357
• Publication Number:
  US 20090194287A1
• Time in Patent Office: 1,289 Days
• Field of Search: 392/301, 392/304, 166/302, 166/60
• US Class Current: 166/302
• 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 heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300° C.

Claims

1. A heating system for a subsurface formation, comprising:

a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

2. The system of claim 1, wherein the ferromagnetic conductor is configured to provide heat to at least a portion of the subsurface formation.

3. The system of claim 1, wherein the ferromagnetic conductor is configured to resistively heat to a temperature of at least about 500°

C.

4. The system of claim 1, wherein at least about 10 m of length of the ferromagnetic conductor is configured to resistively heat to the temperature of at least about 300°

C.

5. The system of claim 1, wherein the ferromagnetic conductor has a thickness of at least 2.1 times the skin depth of the ferromagnetic material in the ferromagnetic conductor at 50°

C. below the Curie temperature of the ferromagnetic material.

6. The system of claim 1, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa.

7. The system of claim 1, wherein the ferromagnetic conductor has different materials along at least a portion of the length of the ferromagnetic conductor that are configured to provide different heat outputs along at least a portion of the length of the ferromagnetic conductor.

8. The system of claim 1, wherein the ferromagnetic conductor has different dimensions along at least a portion of the length of the ferromagnetic conductor that are configured to provide different heat outputs along at least a portion of the length of the ferromagnetic conductor.

9. The system of claim 1, further comprising a corrosion resistant material coating on at least a portion of the ferromagnetic conductor.

10. The system of claim 1, wherein the ferromagnetic conductor is between about 3 cm and about 13 cm in diameter.

11. The system of claim 1, wherein at least about 10 m of length of the ferromagnetic conductor is positioned in a hydrocarbon containing layer in the subsurface formation.

12. The system of claim 1, wherein the electrical conductor is configured to flow electrical current in one direction from the first electrical contact to the second electrical contact.

13. The system of claim 1, wherein the ferromagnetic conductor comprises a ferromagnetic tubular.

14. The system of claim 1, wherein the ferromagnetic conductor comprises two or more ferromagnetic layers, the ferromagnetic layers being separated by insulation layers, wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in each of the ferromagnetic layers such that the ferromagnetic layers resistively heat.

15. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow in a ferromagnetic conductor with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

16. The method of claim 15, further comprising allowing heat to transfer from the ferromagnetic conductor to at least a portion of the subsurface formation.

17. The method of claim 15, further comprising resistively heating the ferromagnetic conductor to a temperature of at least about 500°

C.

18. The method of claim 15, further comprising resistively heating at least about 10 m of length of the ferromagnetic conductor to the temperature of at least about 300°

C.

19. The method of claim 15, wherein the ferromagnetic conductor has a thickness of at least 2.1 times the skin depth of the ferromagnetic material in the ferromagnetic conductor at 50°

C. below the Curie temperature of the ferromagnetic material.

20. The method of claim 15, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa.

21. The method of claim 15, further comprising providing different heat outputs along at least a portion of the length of the ferromagnetic conductor.

22. The method of claim 15, further comprising applying the electrical current to the electrical conductor in one direction from the first electrical contact to the second electrical contact.

23. The method of claim 15, further comprising allowing heat to transfer from the ferromagnetic conductor to at least a portion of the subsurface formation such that hydrocarbons in the formation are mobilized.

24. The method of claim 15, further comprising allowing heat to transfer from the ferromagnetic conductor to at least a portion of the subsurface formation such that hydrocarbons in the formation are mobilized, and producing at least some of the mobilized hydrocarbons from the formation.

25. The method of claim 15, further comprising resistively heating at least one additional ferromagnetic conductor located in the formation, and providing heat from the ferromagnetic conductors such that heat from at least two of the ferromagnetic conductors is superpositioned in the formation and mobilizes hydrocarbons in the formation.

26. A heating system for a subsurface formation, comprising:

a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

a ferromagnetic conductor, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa, and wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats.

27. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow in a ferromagnetic conductor with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa, and wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow such that the ferromagnetic conductor resistively heats.

28. A heating system for a subsurface formation, comprising:

a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces electrical current flow on the inside and outside surfaces of the ferromagnetic conductor such that the ferromagnetic conductor resistively heats.

29. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow on the inside and outside surfaces of a ferromagnetic conductor with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow.

30. A heating system for a subsurface formation, comprising:

a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats; and

wherein the ferromagnetic conductor is configured to have little or no induced current flow at temperatures at and above a selected temperature.

31. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow in a ferromagnetic conductor with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow, wherein the ferromagnetic conductor has little or no resistive heating at temperatures at and above a selected temperature.

32. A system for heating a hydrocarbon containing formation, comprising:

a substantially u-shaped first elongated electrical conductor located in the subsurface formation, wherein the first electrical conductor extends between at least two electrical contacts; and

a first ferromagnetic conductor, wherein the first ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the first electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the first ferromagnetic conductor is electrically insulated from the first electrical conductor to inhibit electrical current flow between the first ferromagnetic conductor and the first electrical conductor;

wherein the first electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the first ferromagnetic conductor such that the first ferromagnetic conductor resistively heats;

a substantially u-shaped second elongated electrical conductor located in the subsurface formation, wherein the second electrical conductor extends between at least two electrical contacts; and

a second ferromagnetic conductor, wherein the second ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the second electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the second ferromagnetic conductor is electrically insulated from the second electrical conductor to inhibit electrical current flow between the second ferromagnetic conductor and the second electrical conductor;

wherein the second electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the second ferromagnetic conductor such that the second ferromagnetic conductor resistively heats; and

wherein the first and second ferromagnetic conductors are configured to provide heat to the formation such that heat from the ferromagnetic conductors is superpositioned in the formation.

33. A method for heating a hydrocarbon containing formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the formation;

inducing electrical current flow in a ferromagnetic conductor with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

resistively heating the ferromagnetic conductor with the induced electrical current flow such that the ferromagnetic conductor resistively heats;

allowing heat to transfer from the ferromagnetic conductor to at least a part of the formation; and

mobilizing at least some hydrocarbons in the part of the formation.

34. A heating system for a subsurface formation, comprising:

a first wellbore extending into the subsurface formation;

a second wellbore extending into the subsurface formation; and

three or more heaters extending between the first wellbore and the second wellbore, at least one heater comprising;

an elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact and a second electrical contact; and

a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

35. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to three or more heaters extending between a first wellbore and a second wellbore, the first and second wellbores extending into the subsurface formation, wherein at least one of the heaters comprises an elongated electrical conductor and a ferromagnetic conductor at least partially surrounding and at least partially extending lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

inducing electrical current flow in the ferromagnetic conductor with the time-varying electrical current in the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

36. A heating system for a subsurface formation, comprising:

a first wellbore extending into the subsurface formation;

a second wellbore extending into the subsurface formation;

a third wellbore extending into the subsurface formation;

a first heater located in the first wellbore, a second heater located in the second wellbore, and a third heater located in the third wellbore, at least one heater comprising;

an elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact and a second electrical contact; and

a ferromagnetic conductor, wherein the ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

37. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a first heater located in a first wellbore, a second heater located in a second wellbore, and a third heater located in a third wellbore, the first, second, and third wellbores extending into the subsurface formation, wherein at least one of the heaters comprises an elongated electrical conductor and a ferromagnetic conductor at least partially surrounding and extending lengthwise around the electrical conductor in a hydrocarbon containing layer in the subsurface formation, and wherein the ferromagnetic conductor is electrically insulated from the electrical conductor to inhibit electrical current flow between the ferromagnetic conductor and the electrical conductor;

inducing electrical current flow in the ferromagnetic conductor with the time-varying electrical current in the electrical conductor; and

resistively heating the ferromagnetic conductor with the induced electrical current flow such that the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.

38. A heating system for a subsurface formation, comprising:

a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

an insulation layer at least partially surrounding the electrical conductor; and

a ferromagnetic sheath at least partially surrounding the insulation layer, the ferromagnetic sheath and the electrical conductor being configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic sheath, or vice versa;

wherein the electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic sheath such that the ferromagnetic sheath resistively heats.

39. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow in a ferromagnetic sheath with the time-varying electrical current in the electrical conductor, wherein the ferromagnetic sheath at least partially surrounds an insulation layer that at least partially surrounds the electrical conductor, the ferromagnetic sheath and the electrical conductor being configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic sheath, or vice versa; and

resistively heating the ferromagnetic sheath with the induced electrical current flow such that the ferromagnetic sheath resistively heats.

40. A heating system for a subsurface formation, comprising:

a first substantially u-shaped electrical conductor located in the subsurface formation, wherein the first electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

a first insulation layer at least partially surrounding the first electrical conductor;

a first ferromagnetic sheath at least partially surrounding the first insulation layer, the first ferromagnetic sheath and the first electrical conductor being configured in relation to each other such that electrical current does not flow from the first electrical conductor to the first ferromagnetic sheath, or vice versa;

a second substantially u-shaped electrical conductor located in the subsurface formation, wherein the first electrical conductor extends between at least the first electrical contact and the second electrical contact;

a second insulation layer at least partially surrounding the second electrical conductor;

a second ferromagnetic sheath at least partially surrounding the second insulation layer, the second ferromagnetic sheath and the second electrical conductor being configured in relation to each other such that electrical current does not flow from the second electrical conductor to the second ferromagnetic sheath, or vice versa; and

a third insulation layer located between the first ferromagnetic sheath and the second ferromagnetic sheath;

wherein the first and second electrical conductors, when energized with time-varying electrical current, induce sufficient electrical current flow in the first and second ferromagnetic sheaths, respectively, such that the ferromagnetic sheaths resistively heat.

41. A method for heating a subsurface formation, comprising:

providing time-varying electrical current to a first substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the first electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation;

inducing electrical current flow in a first ferromagnetic sheath with the time-varying electrical current in the first electrical conductor, wherein the first ferromagnetic sheath at least partially surrounds a first insulation layer that at least partially surrounds the first electrical conductor, the first ferromagnetic sheath and the first electrical conductor being configured in relation to each other such that electrical current does not flow from the first electrical conductor to the first ferromagnetic sheath, or vice versa;

resistively heating the first ferromagnetic sheath with the induced electrical current flow such that the first ferromagnetic sheath resistively heats;

providing time-varying electrical current to a second substantially u-shaped elongated electrical conductor located in the subsurface formation, wherein the second electrical conductor extends between at least the first electrical contact and the second electrical contact;

inducing electrical current flow in a second ferromagnetic sheath with the time-varying electrical current in the second electrical conductor, wherein the second ferromagnetic sheath at least partially surrounds a second insulation layer that at least partially surrounds the second electrical conductor, the second ferromagnetic sheath and the second electrical conductor being configured in relation to each other such that electrical current does not flow from the second electrical conductor to the second ferromagnetic sheath, or vice versa; and

resistively heating the second ferromagnetic sheath with the induced electrical current flow such that the second ferromagnetic sheath resistively heats;

wherein a third insulation layer is located between the first ferromagnetic sheath and the second ferromagnetic sheath.

42. A heating system for a subsurface formation, comprising:

a substantially u-shaped electrical conductor extending into the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

a ferromagnetic conductor at least partially surrounding the electrical conductor in at least a portion of an overburden section of the formation, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa, and wherein the ferromagnetic conductor comprises a plurality of straight, angled, or longitudinally spiral grooves or protrusions that increase the effective circumference of the ferromagnetic conductor;

wherein the straight, angled, or longitudinally spiral grooves or protrusions are configured to inhibit or reduce induction resistance heating in the ferromagnetic conductor.

43. A method for providing current to an electrical resistance heater in a subsurface formation while inhibiting heating in an overburden section of the subsurface formation, comprising:

providing time-varying electrical current to a substantially u-shaped electrical conductor extending through the overburden section of the formation into the subsurface formation, wherein the electrical conductor extends between at least a first electrical contact at a first location on the surface of the formation and a second electrical contact at a second location on the surface of the formation; and

inducing electrical current flow in a ferromagnetic conductor at least partially surrounding the electrical conductor in at least a portion of the overburden section, wherein the ferromagnetic conductor and the electrical conductor are configured in relation to each other such that electrical current does not flow from the electrical conductor to the ferromagnetic conductor, or vice versa, and wherein the ferromagnetic conductor comprises a plurality of straight, angled, or longitudinally spiral grooves or protrusions that increase the effective circumference of the ferromagnetic conductor.

44. A heating system for a subsurface formation, comprising:

a ferromagnetic conductor extending into the subsurface formation, wherein the ferromagnetic conductor is configured to resistively heat when electrical current is applied to, or induced in, the ferromagnetic conductor, and wherein the ferromagnetic conductor resistively heats to a temperature of at least about 300°

C.; and

a plurality of straight, angled, or spiral grooves or protrusions located on at least one surface of the ferromagnetic conductor, wherein the grooves or protrusions increase the effective resistance of the ferromagnetic conductor.

45. A method for heating a subsurface formation, comprising:

applying, or inducing, electrical current in a ferromagnetic conductor extending into the subsurface formation;

resistively heating the ferromagnetic conductor with the electrical current to a temperature of at least about 300°

C., wherein the ferromagnetic conductor comprises a plurality of straight, angled, or spiral grooves or protrusions located on at least one surface of the ferromagnetic conductor that increase the effective resistance of the ferromagnetic conductor; and

allowing heat to transfer from the ferromagnetic conductor to at least a part of the formation.