In situ thermal processing of a hydrocarbon containing formation via backproducing through a heater well
A process for producing hydrocarbons through a heater wellbore positioned in a hydrocarbon containing formation. The in situ treatment process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed, in some embodiments, to transfer from one or more heaters to a selected section of the formation. Heat that is allowed to transfer to the selected section may pyrolyze at least some of the hydrocarbons within the selected section. The process may include, in some embodiments, selectively limiting a temperature proximate a selected portion of a heater wellbore to inhibit coke formation at or near the selected portion. In some embodiments fluids may be produced at certain locations of a heater wellbore such that coke formation is inhibited.
1. A method for treating a hydrocarbon containing formation in situ, comprising:
providing heat from one or more heaters to at least a portion of the formation;
allowing the heat to transfer from the one or more heaters to a part of the formation such that the heat pyrolyzes at least some hydrocarbons in the part of the formation;
selectively limiting a temperature proximate a selected portion of a heater wellbore to inhibit coke formation at or near the selected portion; and
producing at least some hydrocarbons through the selected portion of the heater wellbore.
2. The method of claim 1 , further comprising introducing water in the selected portion to inhibit coke formation at or near the selected portion of the heater wellbore.
3. The method of claim 1 , wherein a portion of the heater wellbore is substantially horizontal in the part of the formation.
4. The method of claim 1 , wherein selectively limiting the temperature comprises providing less heat at the selected portion of the heater wellbore than other portions of the heater wellbore in the part of the formation.
5. The method of claim 1 , wherein selectively limiting the temperature comprises maintaining the temperature proximate the selected portion below pyrolysis temperature of about 250 ° C.
6. The method of claim 1 , further comprising a production well, and producing a mixture from the part of the formation through the production well.
7. The method of claim 1 , further comprising providing at least some heat to an overburden section of the heater wellbore to maintain the produced hydrocarbons in a vapor phase.
8. The method of claim 1 , further comprising maintaining a pressure in the part of the formation below about 150 bars absolute.
9. The method of claim 1 , further comprising producing hydrocarbons when a partial pressure of hydrogen in the formation is at least about 0.5 bars.
10. The method of claim 1 , wherein the heat provided from at least one of the heaters is transferred to a portion of the formation substantially by conduction.
11. The method of claim 1 , wherein a ratio of energy output of the produced mixture to energy input into the formation is at least about 5.
12. The method of claim 1 , wherein the produced mixture comprises an acid number less than about 1.
13. A method for treating a hydrocarbon containing formation in situ, comprising:
providing heat from one or more heaters to a part of the formation:
allowing the heat to transfer directly from the one or more heaters to a selected section of the formation such that the heat pyrolyzes at least some hydrocarbons in the selected section;
controlling operating conditions at a production well to inhibit coking in or proximate the production well; and
producing a mixture from the selected section through the production well.
14. The method of claim 13 , wherein controlling the operating conditions at the production well comprises controlling heat output from at least one of the heaters proximate the production well.
15. The method of claim 13 , wherein controlling the operating conditions at the production well comprises reducing or turning off heat provided from at least one of the heaters for at least part of a time during which the mixture is produced through the production well.
16. The method of claim 13 , wherein controlling the operating conditions at the production well comprises increasing or turning on heat provided from at least one of the heaters to maintain a desired quality in the produced mixture.
17. The method of claim 13 , wherein controlling the operating conditions at the production well comprises producing the mixttwe at a location sufficiently spaced from at least one of the heaters such that coking is inhibited at the production well.
18. The method of claim 13 , further comprising adding steam to the selected section to inhibit coking at the production well.
19. The method of claim 13 , further comprising producing the mixture when a partial pressure of hydrogen in the formation is at least about 0.5 bars.
20. The method of claim 13 , wherein the heat provided from at least one of the heaters is transferred to the selected section of the formation substantially by conduction.
21. The method of claim 13 , wherein a ratio of energy output of the produced mixture to energy input into the formation is at least about 5.
22. The method of claim 13 , wherein the produced mixture comprises an acid number less than about 1.