Temperature limited heater utilizing non-ferromagnetic conductor
First Claim
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1. A heater configured for heating a subsurface formation, comprising:
- an inner electrical conductor comprising electrically conductive material;
a ferromagnetic conductor concentric with the inner electrical conductor, wherein the ferromagnetic conductor at least partially surrounds the inner electrical conductor and is electrically coupled to the inner electrical conductor; and
an electrical conductor concentric with the ferromagnetic conductor and the inner electrical conductor, wherein the electrical conductor at least partially surrounds the ferromagnetic conductor and is electrically coupled to the ferromagnetic conductor and the inner electrical conductor, the ferromagnetic conductor being positioned relative to the electrical conductor and having a thickness such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below a selected temperature;
wherein the heater is located in a wellbore in a hydrocarbon containing layer in the subsurface formation, the heater is at least about 10 m in length in the hydrocarbon containing layer, and the heater is configured to provide heat to at least a portion of the hydrocarbon containing layer surrounding the wellbore.
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Abstract
A heater is described. The heater includes a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor. The ferromagnetic conductor is positioned relative to the electrical conductor such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below or near a selected temperature.
1028 Citations
31 Claims
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1. A heater configured for heating a subsurface formation, comprising:
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an inner electrical conductor comprising electrically conductive material; a ferromagnetic conductor concentric with the inner electrical conductor, wherein the ferromagnetic conductor at least partially surrounds the inner electrical conductor and is electrically coupled to the inner electrical conductor; and an electrical conductor concentric with the ferromagnetic conductor and the inner electrical conductor, wherein the electrical conductor at least partially surrounds the ferromagnetic conductor and is electrically coupled to the ferromagnetic conductor and the inner electrical conductor, the ferromagnetic conductor being positioned relative to the electrical conductor and having a thickness such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below a selected temperature; wherein the heater is located in a wellbore in a hydrocarbon containing layer in the subsurface formation, the heater is at least about 10 m in length in the hydrocarbon containing layer, and the heater is configured to provide heat to at least a portion of the hydrocarbon containing layer surrounding the wellbore. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A heater configured for heating a subsurface formation, comprising:
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an electrical conductor coupled to a ferromagnetic material and an inner electrical conductor, the heater being configured to provide electric resistance heating, and the heater having dimensions such that a majority of the electric resistance heat output is generated in the electrical conductor; wherein the ferromagnetic material is configured to substantially concentrate time-varying electrical current flow to the electrical conductor at temperatures below a selected temperature; wherein the electrical conductor at least partially surrounds the ferromagnetic material and the ferromagnetic material at least partially surrounds the inner electrical conductor, the inner electrical conductor being substantially circular and the ferromagnetic material and the electrical conductor being concentric with the inner electrical conductor; and wherein the heater is located in a wellbore in a hydrocarbon containing layer in the subsurface formation, the heater is at least about 10 m in length in the hydrocarbon containing layer, and the heater is configured to provide heat to at least a portion of the hydrocarbon containing layer surrounding the wellbore. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification