Solution mining and heating by oxidation for treating hydrocarbon containing formations

• US 7,549,470 B2
• Filed: 10/20/2006
• Issued: 06/23/2009
• Est. Priority Date: 10/24/2005
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Vinegar, Harold J., Stegemeier, George Leo
• Primary Examiner(s): SUCHFIELD, GEORGE A
• Application Number:
  US11/584,799
• Publication Number:
  US 20070131415A1
• Time in Patent Office: 977 Days
• Field of Search: None
• US Class Current: 166/245
• CPC Class Codes: C10G 1/002 in combination with oil conversion- or refining processes
• CPC Class Codes: C10G 1/02 by distillation
• CPC Class Codes: C10G 2300/308 Gravity, density, e.g. API
• CPC Class Codes: C10G 9/24 by heating with electrical means
• CPC Class Codes: E21B 43/24 using heat, e.g. steam injection
• CPC Class Codes: E21B 43/2401 by means of electricity
• CPC Class Codes: E21B 43/281 using heat
• CPC Class Codes: E21B 43/34 Arrangements for separating materials produced by the well
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

A method for treating an oil shale formation comprising nahcolite includes providing a first fluid to a portion of the formation. A second fluid is produced from the portion. The second fluid includes at least some nahcolite dissolved in the first fluid. A controlled amount of oxidant is provided to the portion of the formation. Hydrocarbon fluids are produced from the formation.

Claims

1. A method for treating an oil shale formation comprising nahcolite, the method comprising:

providing a first fluid to a portion of the formation;

producing a second fluid from the portion, wherein the second fluid includes at least some nahcolite dissolved in the first fluid;

creating interconnectivity between two or more wellbores in the portion of the formation;

providing heat to at least a part of the portion of the formation from one or more heaters located in the formation;

providing a controlled amount of oxidant to the portion of the formation such that the oxidant flows between at least two of the interconnected wellbores; and

producing hydrocarbon fluids from the formation.

2. The method of claim 1, wherein the first fluid is hot water.

3. The method of claim 1, wherein the first fluid is steam.

4. The method of claim 1, wherein the first fluid is hot water with a temperature below about 250°

C.

5. The method of claim 1, wherein the first fluid is hot water or steam pressurized to a pressure below the fracture pressure of the formation.

6. The method of claim 1, wherein the second fluid also includes carbon dioxide produced from decomposition of a portion of the nahcolite.

7. The method of claim 1, wherein producing nahcolite from the formation creates a permeable zone;

and providing the oxidant to the permeable zone.

8. The method of claim 1, further comprising burning at least a portion of hydrocarbons in the formation with the oxidant, wherein burning of the hydrocarbons provides heat to at least a portion of the formation.

9. The method of claim 1, further comprising heating the first fluid before providing the first fluid to the formation.

10. The method of claim 1, further comprising providing the first fluid through one or more injection wells.

11. The method of claim 1, further comprising providing the heat from the heaters prior to providing the oxidant to the portion of the formation.

12. The method of claim 1, further comprising providing heat from at least one of the heaters to a wellbore region to facilitate oxidation, and wherein heat from such oxidation heats at least a portion of the formation.

13. The method of claim 1, further comprising providing the oxidant through one or more injection wells.

14. The method of claim 1, further comprising:

decomposing at least some dawsonite in the formation with heat;

providing a chelating agent to the formation to dissolve at least some dawsonite decomposition products; and

producing the dissolved dawsonite decomposition products.

15. The method of claim 1, further comprising:

decomposing at least some dawsonite in the formation with heat;

providing a relatively basic fluid to the formation to dissolve at least some dawsonite decomposition products; and

producing the dissolved dawsonite decomposition products.

16. The method of claim 1, wherein controlling the amount of oxidant provided controls heating of the formation.

17. A method for treating an oil shale formation comprising nahcolite, the method comprising:

forming and maintaining a low temperature zone around at least a portion of a subsurface treatment area;

providing a first fluid to a portion of the subsurface treatment area;

producing a second fluid from the portion, wherein the second fluid includes at least some nahcolite dissolved in the first fluid;

creating interconnectivity between two or more wellbores in the portion of the subsurface treatment area;

providing heat to at least a part of the portion of the subsurface treatment area from one or more heaters located in the subsurface treatment area;

providing a controlled amount of oxidant to the portion of the subsurface treatment area such that the oxidant flows between at least two of the interconnected wellbores; and

producing hydrocarbon fluids from the subsurface treatment area.

18. The method of claim 17, wherein forming and maintaining the low temperature zone comprises:

reducing a temperature of heat transfer fluid with a refrigeration system;

circulating the heat transfer fluid through fleeze wells located in a subsurface formation around at least a portion of the subsurface treatment area; and

returning the heat transfer fluid to the refrigeration system.

19. The method of claim 17, wherein controlling the amount of oxidant provided controls heating of the formation.

20. A method for treating an oil shale formation comprising nahcolite, the method comprising:

forming a barrier around at least a portion of a subsurface treatment area, the barrier configured to inhibit fluid from exiting or entering the subsurface treatment area;

providing a first fluid to a portion of the subsurface treatment area;

producing a second fluid from the portion, wherein the second fluid includes at least some nahcolite dissolved in the first fluid;

creating interconnectivity between two or more wellbores in the portion of the subsurface treatment area;

providing heat to at least a part of the poition of the subsurface treatment area from one or more heaters located in the subsurface treatment area;

providing a controlled amount of oxidant to the portion of the subsurface treatment area such that the oxidant flows between at least two of the interconnected wellbores; and

producing hydrocarbon fluids from the subsurface treatment area.

21. The method of claim 20, wherein the barrier is a freeze barrier established by freeze wells.

22. The method of claim 20, wherein the barrier is a sulfur barrier.

23. The method of claim 20, wherein the barrier is a wax barrier.

24. The method of claim 20, wherein controlling the amount of oxidant provided controls heating of the formation.