Degradable casing seal construction for downhole applications
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.
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.