Downhole tools having controlled disintegration and applications thereof

1. A downhole assembly comprising,

a first article comprises a metallic or polymeric member; a degradable polymer shell disposed on the metallic or polymeric member; and an activating material; and

a second article having a surface which accommodates a surface shape of the first article;

wherein the first article is configured to provide a chemical, heat, or a combination thereof to facilitate the disintegration of the second article; the first article is a ball or a plug, and the second article is a ball seat or a frac plug.

2. The downhole assembly of claim 1 , wherein the activating material is disposed between the metallic or polymeric member and the degradable polymer shell.

3. The downhole assembly of claim 1 , wherein metallic member comprises a metal, a metal composite, or a combination comprising at least one of the foregoing.

4. The downhole assembly of claim 1 , wherein the polymeric member comprises a thermo degradable polymer.

5. The downhole assembly of claim 1 , wherein the degradable polymer shell comprises one or more of the following: polyethylene glycol; polyglycolic acid; polylactic acid; polycaprolactone; poly(hydroxyalkanoate); or a copolymer thereof.

6. The downhole assembly of claim 1 , wherein the activating material comprises a solid acid, a pyrotechnic heat source, or a combination comprising at least one of the foregoing.

7. The downhole assembly of claim 6 , wherein the pyrotechnic heat source comprises a metal reducing agent and an oxidizer.

8. The downhole assembly of claim 7 , wherein the pyrotechnic heat source comprises one or more of metal fuels and oxides or salt-based oxidizers.

9. The downhole assembly of claim 8 , wherein the pyrotechnic heat source comprises a combination of barium chromate and zirconium; a combination of potassium perchlorate and iron; a combination of boron, titanium, and barium chromate, or a combination of barium chromate, potassium perchlorate, and tungsten.

10. The downhole assembly of claim 1 , wherein the second article comprises a magnesium alloy.

11. The downhole assembly of claim 1 , wherein the second article further comprises one or more of the following: Ni; W; Mo; Cu; Fe; Cr; Co; or an alloy thereof.

12. The downhole assembly of claim 1 , wherein the second article has a surface coating that is resistant to corrosion by a downhole fluid.

13. The downhole assembly of claim 1 , further comprising a triggering device disposed in the first article.

14. The downhole assembly of claim 13 , wherein the triggering device is effective to generate a spark, an electrical current, or a combination thereof when a predetermined condition is met or when a disintegration signal is received.

15. A method comprising:

disposing a second article in a downhole environment;

disposing a first article on the second article; the second article having a surface which accommodates a surface shape of the first article;

performing a downhole operation;

disintegrating the first article to provide a chemical, heat, or a combination thereof that facilitates the disintegration of the second article; and

disintegrating the second article.

16. The method of claim 15 , further comprising generating a spark, a current, or a combination thereof to trigger the disintegration of the first article.

17. The method of claim 15 , wherein the first article comprises a core and one or more layers surrounding the core, and the method further comprises removing one or more layers and exposing the core to a downhole fluid.

18. The method of claim 15 , wherein the first article is a ball or a plug, and the second article is a ball seat or a frac plug.

19. The method of claim 15 , wherein the first article is disposed after the second article is disposed in the downhole environment.