Sub-Surface Coalbed Methane Well Enhancement Through Rapid Oxidation

• US 20070240880A1
• Filed: 04/13/2006
• Published: 10/18/2007
• Est. Priority Date: 04/13/2006
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Olsen, Thomas
• Granted Patent: US 7,431,083 B2
• Time in Patent Office: Days
• US Class Current: 166/259
• CPC Class Codes: E21B 43/006 Production of coal-bed methane E21B43/243 takes precedence
• CPC Class Codes: E21B 43/116 Gun or shaped-charge perforators
• CPC Class Codes: E21B 43/117 Shaped-charge perforators E21B43/118 takes precedence
• CPC Class Codes: E21B 43/248 using explosives
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping

Abstract

Methods of stimulating production of coalbed methane from a coal-bearing formation are described, one method involving providing a perforation charge comprising a standard charge portion and a charge additive able to produce localized temporary oxidizing environments in perforations; perforating a coal-bearing formation with the perforation charge to form initial perforations defined by carbonaceous material, the initial perforations having localized temporary oxidizing environments in them, and initiating combustion of the carbonaceous material using the oxidizing environments, thus enlarging the initial perforations. Other methods involve perforating the coal-bearing formation with a standard perforation charge, thereby creating perforations; and treating the perforations with a composition creating temporary local oxidizing environments involving an oxidant in the perforations, and initiating combustion of carbonaceous material using the excess oxidant, thus enlarging the perforations.

Claims

1. A method comprising:

(a) providing a wellbore able to access a coal-bearing formation;

(b) providing a perforation charge comprising a standard charge portion and a composition able to produce localized temporary oxidizing environments in perforations;

(c) perforating the coal-bearing formation through the wellbore with the perforation charge to form initial perforations defined by carbonaceous material, the initial perforations having localized temporary oxidizing environments therein; and

(d) initiating combustion of the carbonaceous material using the oxidizing environments, thus enlarging the initial perforations.

2. The method of claim 1 wherein the composition is selected from gases, liquids, solids, and any combination thereof.

3. The method of claim 1 wherein the composition comprises oxidants selected from hypochlorite, hypochloride, hypochlorous acid, hydrogen peroxide, ozone, oxygen, chlorine dioxide, perchlorate, chlorate, persulfate, perborate, percarbonate, permanganate, nitrate, salts of any of these, combinations any of these, and combinations of any salt of these with any of these.

4. The method of claim 1 wherein enlarging the initial perforations comprises increasing any one or more dimension of the initial perforations.

5. The method of claim 1 wherein the wellbore is selected from cased, cased and cemented, and open hole wellbores.

6. The method of claim 1 wherein the combusting creates flow channels of volume larger than the initial perforations.

7. The method of claim 6 wherein the flow channels extend deeper into the coal-bearing formation than the initial perforations.

8. The method of claim 1 comprising injecting a fracturing fluid after the combusting step, the fracturing fluid selected from fluids comprising a proppant and fluids not comprising a proppant.

9. The method of claim 1 comprising removing or bypassing a damaged region of the coal-bearing formation adjacent to the wellbore.

10. The method of claim 8 comprising suddenly decreasing pressure of the wellbore after the combusting step and prior to the injection of a fracturing fluid.

11. A method comprising:

(a) providing a wellbore able to access a coal-bearing formation;

(b) perforating the coal-bearing formation with a standard perforation charge, thereby creating perforations; and

(c) treating the perforations with a composition creating temporary local oxidizing environments comprising an oxidant in the perforations, and initiating combustion of carbonaceous material using the oxidizing environments, thus enlarging the perforations.

12. The method of claim 11 wherein the composition is selected from gases, liquids, solids, and any combination thereof.

13. The method of claim 11 wherein the composition comprises oxidants selected from hypochlorite, hypochloride, hypochlorous acid, hydrogen peroxide, ozone, oxygen, chlorine dioxide, perchlorate, chlorate, persulfate, perborate, percarbonate, permanganate, nitrate, salts of any of these, combinations any of these, and combinations of any salt of these with any of these.

14. The method of claim 11 comprising removing or bypassing a damaged region of the coal-bearing formation adjacent to the wellbore.

15. The method of claim 11 wherein the wellbore is selected from cased, cased and cemented, and open hole wellbores.

16. The method of claim 11 wherein the combusting creates flow channels of volume larger than the perforations.

17. The method of claim 11 wherein the perforating and treating are performed substantially simultaneously by perforating through a pre-pack comprising the composition.

18. A method comprising:

(a) contacting, through a wellbore, surfaces of cleats and fractures of a coal-bearing formation with a composition comprising, or that produces upon contact with the surfaces, localized temporary oxidizing environments in the fractures; and

(b) combusting carbonaceous material in the oxidizing environments under conditions sufficient to oxidize some of the carbonaceous material to enlarge the fractures.

19. The method of claim 18 wherein the composition comprises oxidants selected from hypochlorite, hypochloride, hypochlorous acid, hydrogen peroxide, ozone, oxygen, chlorine dioxide, perchlorate, chlorate, persulfate, perborate, percarbonate, permanganate, nitrate, salts of any of these, combinations any of these, and combinations of any salt of these with any of these.

20. The method of claim 18 wherein the wellbore is selected from cased, cased and cemented, and open hole wellbores.

21. The method of claim 18 wherein the combusting carbonaceous material comprises removing or bypassing a damaged region of the coal-bearing formation adjacent to the wellbore.

22. A method comprising:

(a) providing a wellbore able to access a coal-bearing formation;

(b) injecting into the wellbore a composition creating temporary local oxidizing environments comprising an oxidant; and

(c) perforating the coal-bearing formation with a standard perforation charge, thereby creating perforations and initiating combustion of carbonaceous material using the oxidizing environments.

23. The method of claim 22 wherein the wellbore is selected from cased, cased and cemented, and open hole wellbores.

24. The method of claim 22 wherein the wellbore is cased and the composition is injected into the casing.

25. The method of claim 22 wherein the wellbore is cased and cemented and the composition is injected behind the casing before the cement.