Packers having controlled swelling

1. A sealing system for a flow channel comprising:

a mandrel;

a swellable element disposed about the mandrel, the swellable element comprising one or more of ethylene propylene diene monomer, or styrene butadiene rubber; and

a swell control element disposed on a surface of the swellable element and configured to delay swelling of the swellable element;

wherein the swell control element comprises, based on the total weight of the swell control element:

80 wt % to 99.9 wt % of a polymeric matrix that is impermeable to oil, water, or a combination thereof, the polymer matrix comprising an acrylonitrile butadiene rubber; and

0.1 wt % to 20 wt % of a channel inducer dispersed in the polymeric matrix,

the channel inducer comprising carbon nanotubes or a combination of carbon nanotubes and a hollow fiber.

2. The sealing system of claim 1 , wherein the swell control element has an average thickness of 1.5 mm to 15 mm.

3. The sealing system of claim 1 , wherein the swell control element is chemically bonded to the swellable element.

4. The sealing system of claim 1 , wherein the swell control element is physically bonded to the swellable element.

5. The sealing system of claim 1 , wherein the swell control element encapsulates the swellable element and prevents the swellable element from direct contact with a downhole fluid.

6. The sealing system of claim 1 , wherein the sealing system is a packer or a component of a sand screen.

7. The sealing system of claim 1 , wherein the channel inducer is free of degradable polymers.

8. A sealing system of for a flow channel comprising:

a mandrel;

a swellable element disposed about the mandrel, the swellable element comprising one or more of the following: ethylene propylene diene monomer, styrene butadiene rubber, synthetic rubber based on polychloroprene, fluorosilicone rubber, or isobutylene-isoprene rubber; and

a swell control element disposed on a surface of the swellable element and configured to delay swelling of the swellable element;

wherein the swell control element comprises

a polymeric matrix that is impermeable to oil, water, or a combination thereof; and

a channel inducer dispersed in the polymeric matrix;

wherein

the swell control element comprises, based on the total weight of the swell control element:

50 wt % to 99 wt % of hydrogenated acrylonitrile butadiene rubber as the polymeric matrix, and

1 wt % to 50 wt % of ethylene propylene diene monomer as the channel inducer.

9. A method of sealing, the method comprising:

disposing a sealing system of claim 8 in a wellbore and

allowing the swelling element to swell upon contact with a downhole fluid permeated through the swell control element.

10. The method of claim 9 , wherein the downhole fluid comprises a hydrocarbon, water, brine, an acid, a base, or a combination comprising at least one of the foregoing.

11. The method of claim 9 , wherein the downhole fluid is generated downhole.

12. The method of claim 9 , wherein the downhole fluid is introduced into a wellbore.

13. The method of claim 9 , wherein the downhole fluid is a completion fluid or a drilling fluid.

14. The sealing system of claim 8 , wherein the swellable element comprises ethylene propylene diene monomer.

15. A sealing system for a flow channel comprising:

a mandrel;

a swellable element disposed about the mandrel; and

a swell control element disposed on a surface of the swellable element and configured to delay swelling of the swellable element;

wherein the swell control element comprises

a polymeric matrix that is impermeable to oil, water, or a combination thereof; and

a channel inducer dispersed in the polymeric matrix, wherein the channel inducer comprises a hollow fiber having an average inner capillary tunnel diameter of 1 to 10 microns or a combination of the hollow fiber, having an average inner capillary tunnel diameter of 1 to 10 microns, and carbon nanotubes, and the channel inducer is present in an amount of 0.1 to 20 wt. % based on the total weight of the swell control element.

16. The sealing system of claim 15 , wherein the hollow fiber comprising a glass hollow fiber, a carbon hollow fiber, or a combination comprising at least one of the foregoing.