Downhole tools comprising oil-degradable sealing elements

Patent metadata

Field	Value
Publication number	US-11286741-B2
Application number	US-201414433304-A
Country	US
Kind code	B2
Filing date	May 7, 2014
Priority date	May 7, 2014
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

Downhole tools comprising a body, wherein at least a portion of the body is degradable when exposed to a wellbore environment; and at least one oil-degradable sealing element composed of an oil-degradable elastomer, wherein the oil-degradable sealing element degrades in the wellbore environment. The oil-degradable elastomer is selected from the group consisting of an oil-degradable natural rubber, an oil-degradable synthetic rubber, and any combination thereof.

First claim

The invention claimed is:

1. A downhole tool comprising:
an aqueous-degradable body, wherein at least a portion of the body is degradable when exposed to a wellbore environment; wherein the aqueous-degradable body releases a base during degradation, the base for aiding in degradation of an oil-degradable sealing element, and
the oil-degradable sealing element composed of an oil-degradable elastomer, wherein the oil-degradable sealing element degrades in the wellbore environment, and the oil-degradable sealing element is capable of holding a differential pressure,
wherein the oil-degradable elastomer is an oil-degradable synthetic rubber selected from the group consisting of isobutylene rubber, polyisobutene rubber, silicone rubber, a block polymer of styrene, a block polymer of styrene and butadiene, a block polymer of styrene and isoprene, a polyepichlorohydrin, a copolymer of ethylene oxide/polyepichlorohydrin, a terpolymers of epichlorohydrin/ethylene oxide/allyl glycidyl ether, and any combination thereof,
wherein the oil-degradable sealing element is at least partially encapsulated in a second material forming a permeable sheath for delaying degradation of the oil-degradable sealing element, the oil-degradable sealing element having at least one section able to form a fluid seal between two sections of the wellbore during a wellbore operation and the second material having at least one other section that doesn't interfere with the ability of the oil-degradable sealing element to form the fluid seal.

2. The downhole tool of claim 1 , wherein the body is degradable when exposed to at least one of an aqueous fluid, a wellbore temperature of at least about 93° C., and a hydrocarbon fluid in the wellbore environment.

3. The downhole tool of claim 2 , wherein the aqueous fluid in the wellbore environment further comprises an ionic salt.

4. The downhole tool of claim 1 , wherein the downhole tool is a wellbore zonal isolation device.

5. The downhole tool of claim 4 , wherein the wellbore zonal isolation device is selected from the group consisting of a frac plug, a bridge plug, or a packer.

6. The downhole tool of claim 1 , wherein the portion of the body that is degradable releases another accelerant during degradation, and wherein the another accelerant accelerates the degradation of the oil-degradable sealing element.

7. The downhole tool of claim 1 , wherein the accelerant accelerates the degradation of the portion of the body that is degradable.

8. The downhole tool of claim 1 , wherein the oil-degradable elastomer further comprises a thermoplastic polymer embedded therein.

9. The downhole tool of claim 1 , wherein the accelerant further includes another base, sulfur, a sulfur releasing agent, a peroxide, or a peroxide releasing agent.

10. The downhole tool of claim 1 , wherein the second material is a polyurethane.

11. The downhole tool of claim 1 , wherein the at least a portion of the body comprises an aqueous-degradable body.

12. A method comprising:
installing a downhole tool in a wellbore, wherein the downhole tool comprises a body and at least one oil-degradable sealing element composed of an oil-degradable elastomer rubber; wherein in the installing step, the body comprises an aqueous-degradable body; wherein the aqueous-degradable body releases a base during degradation, the base for aiding in degradation of the oil-degradable sealing element, and
wherein at least a portion of the body is degradable when exposed to the wellbore environment and the oil-degradable sealing element degrades in the wellbore environment;
fluidly sealing two sections of the wellbore with the oil-degradable sealing element of the downhole tool, the oil-degradable sealing element capable of holding a differential pressure;
performing a downhole operation; and
degrading at least a portion of the oil-degradable sealing element such that the oil-degradable sealing element no longer is capable of holding the differential pressure,
wherein the oil-degradable elastomer is an oil-degradable synthetic rubber selected from the group consisting of isobutylene rubber, polyisobutene rubber, silicone rubber, a block polymer of styrene, a block polymer of styrene and butadiene, a block polymer of styrene and isoprene, a polyepichlorohydrin, a copolymer of ethylene oxide/polyepichlorohydrin, a terpolymers of epichlorohydrin/ethylene oxide/allyl glycidyl ether, and any combination thereof,
wherein the oil-degradable sealing element is at least partially encapsulated in a second material forming a sheath, the sheath being permeable permitting fluids therethrough and for delaying degradation of the oil-degradable sealing element.

13. The method of claim 12 , further comprising degrading at least a portion of the portion of the body that is degradable.

14. The method of claim 12 , wherein the body is degradable when exposed to at least one of an aqueous fluid, a wellbore temperature of at least about 93° C., and a hydrocarbon fluid in the wellbore environment.

15. The method of claim 14 , wherein the aqueous fluid further comprises an ionic salt.

16. The method of claim 12 , wherein the portion of the body that is degradable releases another accelerant during degradation, and wherein the another accelerant accelerates the degradation of the oil-degradable sealing element.

17. The method of claim 12 , wherein the accelerant accelerates the degradation of the portion of the body that is degradable.

18. The method of claim 12 , wherein the oil-degradable elastomer further comprises a thermoplastic polymer embedded therein.

19. The method of claim 12 , wherein the downhole operation is a fluid injection operation.

20. The method of claim 19 , wherein the fluid injection operation is a hydraulic fracturing operation.

21. The method of claim 12 , wherein the accelerant further includes a base, sulfur, a sulfur releasing agent, a peroxide, or a peroxide releasing agent.

22. The method of claim 12 , further comprising a frangible sheath encapsulating the at least one oil-degradable sealing element, the frangible sheath comprising a polyurethane.

23. The method of claim 12 , wherein in the degrading step, the oil-degradable sealing element releases an accelerant.

24. A system comprising:
a wellbore; and
a downhole tool capable of being disposed in the wellbore to fluidly seal two sections thereof, the downhole tool comprising a body and at least one oil-degradable sealing element composed of an oil-degradable elastomer and the oil-degradable sealing element is capable of holding a differential pressure; wherein the body comprises an aqueous-degradable body; wherein the aqueous-degradable body releases a base during degradation, the base for aiding in degradation of the oil-degradable sealing element,
wherein at least a portion of the body is degradable when exposed to the wellbore environment and the oil-degradable sealing element degrades in the wellbore environment,
wherein the oil-degradable elastomer is an oil-degradable synthetic rubber selected from the group consisting of isobutylene rubber, polyisobutene rubber, silicone rubber, a block polymer of styrene, a block polymer of styrene and butadiene, a block polymer of styrene and isoprene, a polyepichlorohydrin, a copolymer of ethylene oxide/polyepichlorohydrin, a terpolymers of epichlorohydrin/ethylene oxide/allyl glycidyl ether, and any combination thereof, and,
wherein the oil-degradable sealing element is at lea

Assignees

• Halliburton Energy Services Inc

Inventors

• Fripp Michael Linley
• Murphree Zachary
• Walton Zach
• Smith Charles Timothy

Classifications

• E21B43/26

  by forming crevices or fractures · CPC title

• E21B33/134 Primary

  Bridging plugs · CPC title

• E21B33/12 Primary

  Packers; Plugs (used for cementing E21B33/134, E21B33/16) · CPC title

• C09K8/5083

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• E21B33/128

  with a member expanded radially by axial pressure (E21B33/122, E21B33/124 take precedence) · CPC title