Degradable material assisted diversion or isolation

• US 20060113077A1
• Filed: 12/05/2005
• Published: 06/01/2006
• Est. Priority Date: 09/01/2004
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Fredd, Christopher N., Willberg, Dean, Sullivan, Philip F., Bulova, Marina, Boney, Curtis L., Lassek, John, Hoefer, Ann M.W., Vostrukhov, Alexey
• Granted Patent: US 7,380,600 B2
• Time in Patent Office: Days
• US Class Current: 166/280.100
• CPC Class Codes: C09K 8/42 Compositions for cementing, e.g. for cementing casings into boreholes; Compositions for plugging, e.g. for killing wells compositions for plastering C09K8/50
• CPC Class Codes: C09K 8/467 containing additives for specific purposes
• CPC Class Codes: C09K 8/508 macromolecular compounds C09K8/512 takes precedence
• CPC Class Codes: C09K 8/68 containing organic compounds
• CPC Class Codes: C09K 8/76 for preventing or reducing fluid loss
• CPC Class Codes: C09K 8/80 Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A method for well treatment by forming a temporary plug in a fracture, a perforation, a wellbore, or more than one of these locations, in a well penetrating a subterranean formation is provided, in which the method of well treatment includes: injecting a slurry comprising a degradable material, allowing the degradable material to form a plug in a perforation, a fracture, or a wellbore in a well penetrating a formation; performing a downhole operation; and allowing the degradable material to degrade after a selected time such that the plug disappears.

Claims

1. A method of well treatment, comprising:

a) injecting a slurry comprising a degradable material,

b) allowing the degradable material to form a plug in one or more than one of a perforation, a fracture, and a wellbore in a well penetrating a formation;

c) performing a downhole operation; and

d) allowing the degradable material to at least partially degrade after a selected duration such that the plug disappears.

2. The method of claim 1, wherein the degradable material comprises a polymer of an ester.

3. The method of claim 2, wherein the polymer is selected from a polymer of lactide, glycolide, polylactic acid, polyglycolic acid, and mixtures thereof.

4. The method of claim 1, wherein the degradable material comprises a polymer of an amide.

5. The method of claim 4, wherein the polymer comprises polyacrylamide.

6. The method of claim 1, wherein the degradable material is present at a concentration of no less than 40 lbm/1,000 gal (4.8 g/L).

7. The method of claim 1, further comprising injecting a second material to induce a screenout.

8. The method of claim 1, wherein the degradable material is a fiber.

9. The method of claim 1, wherein the slurry further comprises a particulate material.

10. The method of claim 9, wherein the particulate material is degradable

11. The method of claim 8, wherein the particulate material is a proppant.

12. The method of claim 11 wherein the degradable material is a fiber.

13. The method of claim 11, wherein the proppant comprises particles having a distribution of sizes.

14. The method of claim 1, wherein the slurry further comprises an additive for delaying degradation of the degradable material.

15. The method of claim 1, wherein the slurry further comprises an additive for accelerating degradation of the degradable material.

16. The method of claim 1, further comprising modeling to optimize parameters for the well treatment, wherein the step of injecting the slurry is based on the optimized parameters.

17. The method of claim 16, wherein the optimized parameters comprise the selected duration before the degradable material degrades.

18. The method of claim 1, wherein the well penetrating the formation is cased.

19. The method of claim 1, wherein the downhole operation comprises well stimulation.

20. The method of claim 19, wherein the well stimulation comprises hydraulic fracturing.

21. The method of claim 20, wherein the hydraulic fracturing comprises injecting a pad, said pad comprising a fiber comprising a degradable material.

22. The method of claim 20, wherein hydraulic fracturing is applied to more than one layer of a multilayer formation.

23. The method of claim 22, wherein the step of injecting the slurry is performed at the tail end of fracturing a layer.

24. The method of claim 23, wherein no bridge plug or sand plug is placed in the wellbore before fracturing a subsequent layer.

25. The method of claim 23, wherein the degradable material forms the plug in the fracture by bridging with proppants in the fracture.

26. The method of claim 19, wherein the well stimulation comprises acid fracturing.

27. The method of claim 19, wherein the well stimulation comprises a waterfrac.

28. The method of claim 1, wherein the downhole operation is selected from well repair and installation of downhole equipment.

29. The method of claim 1, wherein the selected duration is between 0.5 and 6 hours.

30. The method of claim 1, wherein the step of injecting the slurry is via coiled tubing installed in the well.

31. The method of claim 1 wherein the degradable material comprises a polyvinyl ester.

32. The method of claim 31 wherein the polyvinyl ester comprises partially hydrolyzed polyvinyl acetate.

33. The method of claim 1, wherein degradation of the material is assisted by a wash.

34. The method of claim 1, wherein degradation of the material is assisted by increasing the temperature.

35. The method of claim 1, wherein the treatment is used to isolate a region selected from a fracture, a production zone, and a part of the wellbore, wherein the part of the wellbore is above the formation pressure.

36. The method of claim 1, wherein the degradable material is selected from limestone fibers and glass fibers.