Degradable casing seal construction for downhole applications

Patent metadata

Field	Value
Publication number	US-9777550-B2
Application number	US-201414552003-A
Country	US
Kind code	B2
Filing date	Nov 24, 2014
Priority date	Nov 24, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

In one aspect, a degradable apparatus is disclosed, including: an inner core with a first degradation rate in a downhole environment; an outer sheath disposed around an outer extent of the inner core with a second degradation rate less than the first degradation rate in the downhole environment. In another aspect, a method of temporarily sealing a downhole zone is disclosed, including: providing an inner core with a first degradation rate in a downhole environment; providing an outer sheath disposed around an outer extent of the inner core with a second degradation rate less than the first degradation rate in the downhole environment; sealing the downhole zone with the outer sheath; exposing the outer sheath to the downhole environment; and exposing the inner core to the downhole environment.

First claim

The invention claimed is:

1. A degradable apparatus, comprising:
an inner core with a first degradation rate in a downhole environment;
an outer sheath disposed around an outer extent of the inner core that degrades at a second degradation rate less than the first degradation rate in the downhole environment, wherein the outer sheath is configured to seal against a casing.

2. The apparatus of claim 1 , wherein the downhole environment has a temperature greater than 100 degrees Fahrenheit and less than 350 degrees Fahrenheit.

3. The apparatus of claim 1 , wherein the downhole environment includes a salt water content.

4. The apparatus of claim 1 , wherein the outer sheath is formed in a wedge shape.

5. The apparatus of claim 1 , wherein the outer sheath is formed of at least one of a group consisting of: TDI, MDI, PPDI, polyether, polyesther, polycaprolactone, and polycarbonate.

6. The apparatus of claim 1 , wherein the core is formed of at least one of a group consisting of: polymer, controlled electrolytic metallic, adipic acid, and citric acid.

7. The apparatus of claim 1 , further comprising at least one fluid communication channel formed through the outer sheath to expose the inner core to the downhole environment.

8. The apparatus of claim 7 , wherein degradation of the inner core accelerates degradation of the outer sheath.

9. A method of temporarily sealing a downhole zone, comprising:
providing an inner core with a first degradation rate in a downhole environment;
providing an outer sheath disposed around an outer extent of the inner core that degrades at a second degradation rate less than the first degradation rate in the downhole environment;
sealing the downhole zone with the outer sheath, wherein the outer sheath is configured to seal against a casing;
exposing the outer sheath to the downhole environment;
degrading the outer sheath in response to exposure to the downhole environment; and
exposing the inner core to the downhole environment.

10. The method of claim 9 , wherein the downhole environment has a temperature of at least 100 degrees Fahrenheit and no greater than 350 degrees Fahrenheit.

11. The method of claim 9 , wherein the downhole environment includes a salt water content.

12. The method of claim 9 , wherein the outer sheath is formed in a wedge shape.

13. The method of claim 9 , wherein the outer sheath is formed of at least one of a group consisting of: TDI, MDI, PPDI, polyether, polyesther, polycaprolactone, and polycarbonate.

14. The method of claim 9 , wherein the core is formed of at least one of a group consisting of: polymer, controlled electrolytic metallic, adipic acid, and citric acid.

15. The method of claim 9 , further comprising forming at least one fluid communication channel through the outer sheath to expose the inner core to the downhole environment.

16. The method of claim 15 , wherein degradation of the inner core accelerates degradation of the outer sheath.

17. A downhole system, comprising:
a casing string disposed in a wellbore; and
a casing seal configured to seal against the casing string, including:
an inner core with a first degradation rate in a downhole environment;
an outer sheath disposed around an outer extent of the inner core that degrades at a second degradation rate less than the first degradation rate in the downhole environment.

18. The system of claim 17 , wherein the downhole environment has a temperature of at least 100 degrees Fahrenheit and no greater than 350 degrees Fahrenheit.

19. The system of claim 17 , wherein the downhole environment includes a salt water content.

20. The system of claim 17 , wherein the outer sheath is formed in a wedge shape.

21. The system of claim 17 , wherein the outer sheath is configured to seal against a casing.

22. The system of claim 17 , wherein the outer sheath is formed of at least one of a group consisting of: TDI, MDI, PPDI, polyether, polyesther, polycaprolactone, and polycarbonate.

23. The system of claim 17 , further comprising at least one fluid communication channel formed through the outer sheath to expose the inner core to the downhole environment.

24. The system of claim 23 , wherein degradation of the inner core accelerates degradation of the outer sheath.

Assignees

• Doane James
• Furlan Wayne
• Duan Ping
• Roy Sayantan
• Sadana Anil
• Baker Hughes Inc

Inventors

• Doane James
• Furlan Wayne
• Duan Ping
• Roy Sayantan
• Sadana Anil

Classifications

• E21B33/1208 Primary

  characterised by the construction of the sealing or packing means (E21B33/1277 takes precedence) · CPC title

• E21B2200/08

  Down-hole devices using materials which decompose under well-bore conditions · CPC title