Temperature limited heaters using phase transformation of ferromagnetic material
AssigneeShell Oil Company
InventorsJohn Michael Vitek, Michael Patrick Brady, Joseph Arno Horton, Jr.
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Abstract
Systems, methods, and heaters for treating a subsurface formation are described herein. Systems and methods for making heaters are described herein. At least one heater includes a ferromagnetic conductor and an electrical conductor. The electrical conductor is electrically coupled to the ferromagnetic conductor. The heater provides a first amount of heat at a lower temperature. The heater may provide a second reduced amount of heat when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.
Claims28
A heater, comprising:
- a ferromagnetic conductor;
- and
- an electrical conductor electrically coupled to the ferromagnetic conductor;
- wherein the heater is configured to provide a first amount of heat at a lower temperature and, the heater is configured to provide a second reduced amount of heat when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.
A heater, comprising:
- a ferromagnetic conductor;
- an electrical conductor electrically coupled to the ferromagnetic conductor;
- wherein the electrical conductor provides a majority of a resistive heat output of the heater at temperatures up to approximately the selected temperature, or the selected temperature range, of the phase transformation of the ferromagnetic conductor;
- and
- the heater is configured to provide a first amount of heat at a lower temperature and, the heater is configured to provide a second reduced amount of heat when the heater reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.
A method of heating a subsurface formation, comprising:
- providing electrical current to a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor to provide heat to at least a portion of the subsurface formation;
- wherein a first amount of heat is provided at a lower temperature and, a second reduced amount of heat is provided when the ferromagnetic conductor reaches a selected temperature, or enters a selected temperature range, at which the ferromagnetic conductor undergoes a phase transformation.
Dependencies are inferred from the claim text.