Patent EA-004326-B1 (EA)
Title: Method and system for treating a hydrocarbon containing formation
Inventor: BERCHENKO ILYA EMIL
IPC: E21B36/00
Filed: 2001-04-24
Abstract: 1. A method for treating a hydrocarbon containing formation in situ and producing a hydrocarbon fluid from the formation, which method comprises pyrolysing hydrocarbons present in the formation during the production of the hydrocarbon fluid from the formation with the application of a pressure/temperature controls-characterized in that the pressure is at least the pressure which can be calculated for a selected temperature, or the temperature is at most the temperature which can be calculated for a selected pressure from the equation wherein P is pressure (bar absolute), T is temperature ( degree C) and A and B are predetermined parameters, and wherein A is at least 5000, B is at least 10 and P is at most 72 bar absolute to control a property which is relevant to the quantity, the composition and/or the quality of the hydrocarbon fluids produced. 2. A method as claimed in claim 1, wherein the hydrocarbon containing formation comprises a kerogen, such as coal or oil shale, or heavy hydrocarbons, such as a tar sand. 3. A method as claimed in claim 1 or 2, wherein a heat source is applied, which is configured for heating the hydrocarbon formation substantially by conductive heating. 4. A method as claimed in any of claims 1-3, wherein at least a substantial portion of hydrocarbons present in the formation are pyrolysed by heating at a. temperature below 450 degree C, preferably in the range of from 250 degree C to 400 degree C, in particular in the range of from 260 degree C to 375 degree C. 5. A method as claimed in any of claims 1-4, wherein the pressure is at least 1.4 bar and wherein if the pressure is 3.52 bar and the pyrolysis takes place at a temperature up to 301.7 degree C a heating source is applied other than a heating source which solely provides radio frequency heating. 6. The method as claimed in claim 1, which method comprises pyrolysing hydrocarbons present in the formation during the production of the hydrocarbon fluid from the formation with the application of a pressure/temperature control, and in the presence of hydrogen at a partial pressure of hydrogen of at least 0.5 bar, for example in the range of from 1 bar to 10 bar, in particular from 5 bar to 7 bar. 7. A method as claimed in any of claims 1-6, wherein A equals 14000 and B equals 25. 8. A method as claimed in any of claims 1-6, wherein A equals 24146 and B equals 43.349. 9. A method as claimed in any of claims 1-6, wherein A equals 30864 and B equals 50.676- 10. A method as claimed in claim 9, wherein A equals 16947 and B equals 33.603. 11. A method as claimed in any of claims 1-6, wherein A equals 57379 and B equals 83.145. 12. A method as claimed in any of claims 1-6, wherein A equals 5492.8 and B equals 14.234. 13. A method as claimed in any of claims 1-6, wherein A equals 38360 and B equals 60.531. 14. A method as claimed in any of claims 1-6, wherein A equals 6613.1 and B equals 16.364. 15. A method as claimed in any of claims 1-6, wherein A equals 28554 and B equals 47.084. 16. A method as claimed in any of claims 1-6, wherein A equals 11118 and B equals 23.156. 17. A method as claimed in any one of claims 1-16, wherein subsequent to the step of treating at least part of the formation by pyrolysis at least part of the treated hydrocarbon containing formation is reacted with a synthesis gas generating fluid to produce a synthesis gas. 18. A method as claimed in claim 17, wherein the synthesis gas is converted into hydrocarbons. 19. A method as claimed in claim 18, wherein the synthesis gas is converted into paraffins by a Fischer-Tropsch hydrocarbon synthesis process and the paraffins are converted in a hydrocracker. 20. A method of producing energy comprising providing a synthesis gas which synthesis gas has been produced according to claim 17 and expanding and/or combusting the synthesis gas or using the synthesis gas in a fuel cell. 21. A system for use in the method according to any one of claims 1 to 16, the system comprising one or more heat injection wells and one or more hydrocarbon fluid production wells which are each located at one or more selected distances from said one or more heat injection wells and which are provided with pressure control devices which are adapted to maintain an elevated fluid pressure (P) in a heated part of the formation between one or more heat injection wells and one or more production wells; characterized in that the heat injection wells and pressure control devices are controlled such that the pressure is at least the pressure which can be calculated for a selected temperature, or the temperature is at most the temperature which can be calculated for a selected pressure from the equation wherein P is pressure (bar absolute), T is temperature ( degree C) and A and B are predetermined parameters, and wherein A is at least 5000, B is at least 10 and P is at most 72 bar absolute to control a property which is relevant to the quantity, the composition or the quality of the hydrocarbon fluids produced. 22. The system of claim 21, wherein each hydrocarbon fluid production well is provided with a pressure control device which maintains the pressure within at least part of the wellbore of the production well at a pre-set value which is determined in relation to an assessed temperature in the pyrolysis zone from which in use pyrolysed hydrocarbon fluids flow through the formation into the wellbore of the production well. 23. The system of claim 21, wherein a plurality of heat injection wells are located at one or more selected distances and in a substantially triangular pattern around each production well. 24. The system of claim 21, wherein at least one of the heat injection and production wells is drilled substantially parallel to the upper and lower boundaries of the hydrocarbon bearing formation. 25. The system of claim 21, wherein at least one of the heat injection and production wells is drilled substantially orthogonal to the upper and lower boundaries of the hydrocarbon bearing formation. 26. The system of claim 21, wherein at least one of the heat injection wells comprises: an oxidizing fluid supply conduit to provide an oxidizing fluid from an oxidizing fluid source to a reaction zone in the formation during use, and wherein the oxidizing fluid is selected to oxidize at least a portion of the hydrocarbons in the formation in the vicinity of the wellbore zone during use such that heat is generated at the reaction zone; and a combustion gases exhaust conduit for venting combustion gases from the reaction zone to the earth surface to allow heat to transfer substantially by conduction from the reaction zone to a selected section of the formation during use. 27. The system of claim 26, wherein the oxidant injection and combustion gases exhaust conduits are equipped with pressure regulation devices which control the pressure in the heater well such that at least a substantial part of the combustion gases generated at the reaction zone are vented to the earth surface through the combustion gases exhaust conduit. 28. The system of claim 26 or 27, wherein the oxidant injection conduit and the combustion gases exhaust conduit extend co-axially to each other from a wellhead of the heater well into the hydrocarbon bearing formation, the oxidant injection conduit protrudes from the lower end of the combustion gases exhaust conduit through a reaction zone traversing the hydrocarbon bearing formation and the protruding lower part of the oxidant injection conduit is equipped with an array of oxidant injection orifices for- injecting oxidant into an annular space between the oxidant injection conduit and the reaction zone. 29. The system of claim any one of claims 21 to 28, wherein at least one heater well comprises an electric heater. 30. The system of claim 29, wherein the electric heater comprises: a mineral insulated cable disposed within an uncased section of the wellbore of the heater well which extend through the hydrocarbon containing formation, wherein the mineral insulated cable is configured to provide radiant heat to at least a portion of the formation during use; and wherein the system is configured to allow heat to transfer from the mineral insulated cable to a section of the formation during use. 31. The system of claim 30, wherein the mineral insulated cable comprises a conductor comprising a copper-nickel alloy, which conductor is disposed in an insulating mineral material which comprises magnesium oxide and/or other mineral grain particles which are disposed in a sheath comprising a corrosion-resistant material. 32. The system of claim 29, wherein the electric heater comprises a first electrical conductor disposed in a first conduit, which is disposed within the heater well. 33. The system of claim 32, further comprising a sliding electrical connector coupled to the first conductor and/or the first conduit and wherein a fluid is disposed within the first conduit, wherein the fluid is configured to maintain a pressure within the first conduit to substantially prevent deformation of the first conduit during use. 34. The system of claim 32, further comprising a tube disposed within an annular opening external to the first conduit, wherein the tube is configured to remove vapour produced from at least the heated portion of the formation such that a pressure balance is maintained between the first conduit and the opening to substantially prevent deformation of the first conduit during use. 35. The system of claim 29, wherein the electric heater comprises at least one elongate electrical conductor member, which is arranged in an at least partly uncased section of the heater well. 36. The system of claim 35, wherein a fluid supply conduit is disposed within the heater well for injecting a cleaning fluid, such as air, at the surface of the electrical conductor member to inhibit deposition of combustion products on or proximate to at least the one elongate electrical conductor member during use. 37