Self-degrading fibers and associated methods of use and manufacture

• US 20060169449A1
• Filed: 01/31/2005
• Published: 08/03/2006
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Todd, Bradley L., Mang, Michael N.
• Granted Patent: US 7,267,170 B2
• Time in Patent Office: Days
• US Class Current: 166/278
• CPC Class Codes: C09K 2208/08 Fiber-containing well treatment fluids
• CPC Class Codes: C09K 8/467 containing additives for specific purposes
• CPC Class Codes: C09K 8/70 characterised by their form or by the form of their components, e.g. foams
• CPC Class Codes: D01D 5/24 with a hollow structure; Spinnerette packs therefor D01D5/38 takes precedence; producing tubes of plastic material B29D; addition of agents forming hollow filaments D01F1/08
• CPC Class Codes: D01F 6/625 derived from hydroxy-carboxylic acids, e.g. lactones

Abstract

This invention relates to the use of degradable fibers, and more particularly, to self-degrading fibers and their associated methods of use and manufacture. In one embodiment, the present invention provides a method of treating a portion of a subterranean formation comprising the steps of: providing a treatment fluid comprising a plurality of self-degrading fibers, the self-degrading fibers comprising an outer shell and a core liquid; placing the treatment fluid into a subterranean formation; and treating a portion of the subterranean formation.

Claims

1. A method of treating a portion of a subterranean formation comprising the steps of:

providing a treatment fluid comprising a plurality of self-degrading fibers, the self-degrading fibers comprising an outer shell and a core liquid;

placing the treatment fluid into a subterranean formation; and

treating a portion of the subterranean formation.

2. The method of claim 1 wherein at least one of the self-degrading fibers comprises a coating and/or an additive.

3. The method of claim 1 wherein at least one of the self-degrading fibers has at least one of the following:

a round cross-sectional shape;

an oval cross-sectional shape;

a trilobal shape;

a star shape;

a flat shape;

a rectangular shape;

a closed fiber end;

a diameter of about 2 microns to about 200 microns;

a length of at least about 1 millimeter;

an aspect ratio of greater than about 100;

or a density of about 1 to about 4 g/cm³.

4. The method of claim 1 wherein the concentration of self-degrading fibers in the treatment fluid is about 0.01% to about 75% of the composition of the treatment fluid.

5. The method of claim 1 wherein the outer shell of at least one of the self-degrading fibers comprises at least one of the following:

an aliphatic polyester;

a poly(lactide);

a poly(glycolide);

a poly(ε

-caprolactone);

a poly(hydroxybutyrate);

a polyanhydride;

an aliphatic polycarbonate;

a poly(orthoester);

a poly(amide);

a poly(urethane);

a poly(hydroxy ester ether);

or a poly(phosphazene).

6. The method of claim 1 wherein the core liquid of at least one of the self-degrading fibers comprises at least one of the following:

an alcohol, an acid, a base or an aqueous-based fluid.

7. The method of claim 1 wherein the treatment fluid is a cement composition, a fracturing fluid, or a gravel pack fluid.

8. The method of claim 1 wherein treating the subterranean formation involves a primary cementing operation, placing a permeable cement pack, placing a permeable proppant pack, or placing a gravel pack.

9. The method of claim 1 wherein at least one of the self-degrading fibers has a plurality of core liquids.

10. A method comprising:

providing a cement composition that comprises a hydraulic cement, water, and a plurality of self-degrading fibers, the self-degrading fibers comprising an outer shell and a core liquid;

placing the cement composition in a subterranean formation; and

allowing the cement composition to set therein.

11. The method of claim 10 wherein the outer shell of at least one of the self-degrading fibers comprises at least one of the following:

an aliphatic polyester;

a poly(lactide);

a poly(glycolide);

a poly(ε

-caprolactone);

a poly(hydroxybutyrate);

a polyanhydride;

an aliphatic polycarbonate;

a poly(orthoester);

a poly(amide);

a poly(urethane);

a poly(hydroxy ester ether);

or a poly(phosphazene).

12. The method of claim 10 wherein at least one of the self-degrading fibers has at least one of the following:

a round cross-sectional shape;

an oval cross-sectional shape;

a trilobal shape;

a star shape;

a flat shape;

a rectangular shape;

a closed fiber end;

a diameter of about 2 microns to about 200 microns;

a length of at least about 1 millimeter;

an aspect ratio of greater than about 100;

or a density of about 1 to about 4 g/cm³.

13. The method of claim 10 wherein the core liquid of at least one of the self-degrading fibers comprises at least one of the following:

an alcohol, an acid, a base or an aqueous-based fluid.

14. A method of fracturing a portion of a subterranean formation comprising:

providing a fracturing fluid composition that comprises proppant particulates and a plurality of self-degrading fibers, the self-degrading fibers comprising an outer shell and a core liquid;

injecting the fracturing fluid into the subterranean formation at a pressure sufficient to create or enhance a fracture in a portion therein;

allowing the proppant particulates and self-degrading fibers to conglomerate within the fracture so as to form a permeable proppant matrix therein.

15. The method of claim 14 wherein the fracturing fluid comprises a hydraulic cement.

16. The method of claim 14 wherein the fracturing fluid comprises a base fluid and a viscosifying agent.

17. The method of claim 14 wherein the outer shell of at least one of the self-degrading fibers comprises at least one of the following:

an aliphatic polyester;

a poly(lactide);

a poly(glycolide);

a poly(ε

-caprolactone);

a poly(hydroxybutyrate);

a polyanhydride;

an aliphatic polycarbonate;

a poly(orthoester);

a poly(amide);

a poly(urethane);

a poly(hydroxy ester ether);

or a poly(phosphazene).

18. A method of providing some degree of sand control to a portion of a subterranean formation penetrated by a well bore comprising:

providing a gravel pack fluid comprising gravel particulates and a plurality of self-degrading fibers, the self-degrading fibers comprising an outer shell and a core liquid; and

placing the gravel pack fluid into the subterranean formation so that a permeable gravel pack forms adjacent to a portion of the subterranean formation.

19. The method of claim 18 wherein the self-degrading fibers produce an acid upon degradation that is capable of interacting with an acid soluble portion of a filter cake.

20. The method of claim 18 wherein before placing the gravel pack fluid into the subterranean formation, a perforated shroud having perforations is placed into the subterranean formation, the perforations being sealed by a temporary sealant, and the gravel pack fluid is placed between the perforated shroud and the portion of the subterranean formation.