Patent EA-004096-B1 (EA)
Title: Electrical well heating system and method
Inventor: DE ROUFFIGNAC ERIC
IPC: E21B43/24
Filed: 2001-04-24
Abstract: 1. A system configured to heat an underground hydrocarbon containing formation to pyrolyse hydrocarbons within the formation, comprising: an electrical conductor configured to be disposed within a heater well traversing the formation to provide radiant heat to at least a portion of the formation during use, wherein the electrical conductor is at least partly surrounded by an electrical insulation layer which comprises an insulating mineral material, characterized in that the electrical conductor is disposed within an at least partly uncased fluid filled section of the heater well. 2. The system of claim 1, wherein the insulating mineral material comprises mineral grain particles and a selected amount of impurities. 3. The system of claim 2, wherein the impurities comprise grain particles having smaller sizes than the mineral grain particles. 4. The system of any one of claims 1 to 3, wherein the insulating mineral material is disposed in a sheath, which comprises a corrosion-resistant material. 5. The system of claim 1, wherein the electrical conductor comprises a copper-nickel alloy and is configured as a substantially flexible cable. 6. The system of any one of claims 1 to 5, further comprising a support member, which is configured to support the mineral insulated electrical conductor. 7. The system of claim 6, further comprising a support member and a centralizer, wherein the support member is configured to support the mineral insulated electrical conductor, and wherein the centralizer is configured to maintain a location of the mineral insulated conductor on the support member. 8. The system of claim 1, wherein the mineral insulated electrical conductor is configured to generate in use a controlled amount of radiant heat to heat the formation surrounding the well. 9. The system of claim 8, wherein the mineral insulated electrical conductor is configured to generate during use between 0.5 and 2 KW radiant heat per meter length of the mineral insulated electrical conductor. 10. An in situ method for heating a carbon containing formation to pyrolyse hydrocarbons within the formation, comprising: applying an electrical current to a mineral insulated electrical conductor to provide radiant heat to at least a portion of the formation, and allowing the radiant heat to transfer from the mineral insulated conductor to a section of the formation, characterized in that the mineral insulated conductor is disposed within an at least partly uncased fluid filled section of a heater well traversing the formation. 11. The method of claim 10, further comprising supporting the mineral insulated conductor on a support member, which is suspended within the heater well. 12. The method of claim 11, further comprising supporting the mineral insulated conductor on the support member with a number of centralizers. 13.The method of claim 10, wherein the mineral insulated conductor is configured as a substantially flexible cable, which comprises a copper-nickel alloy. 14. The method of claim 10, wherein the mineral insulated conductor is disposed in a tubular layer of insulating mineral material, and wherein the insulating mineral material comprises magnesium oxide grain particles. 15. The method of claim 10, wherein the mineral insulated cable comprises a conductor disposed in an insulating mineral material, wherein the insulating material comprises mineral grain particles and a selected amount of impurities and is disposed in a sheath, and wherein the sheath comprises a corrosion-resistant material. 16. The method of claim 10, further comprising heating at least a portion of the formation surrounding the heater well to substantially pyrolyze hydrocarbons within said portion of the formation surrounding the heater well. 17. The method of claim 16, comprising transmitting between 0.5 and 1.5 KW radiant heat per meter length of the mineral insulated conductor into a portion of the hydrocarbon containing formation surrounding the heater well. 18. The method of any one of claims 10-17, wherein the fluid pressure in the heater well is controlled by a pressure control assembly.