Swellable packer with enhanced operating envelope
A swellable packer can include a base pipe, at least one swellable seal on the base pipe, the seal comprising a swellable material, and at least one other swellable seal on the base pipe, the other swellable seal comprising another swellable material, and the swellable materials being different materials. Another swellable packer can include at least one swellable seal, the seal comprising a swellable material, and at least one other swellable seal, the other swellable seal comprising another swellable material, and wherein one swellable seal displaces the other swellable seal into contact with a well surface, in response to contact between the one swellable seal and an activating agent.
1. A swellable packer, comprising:
a base pipe;
at least one first swellable seal on the base pipe, the first seal comprising a first swellable material; and
at least two second swellable seals on the base pipe, the second swellable seals comprising a second swellable material, and the first and second swellable materials being different materials, wherein two of the second swellable seals longitudinally straddle the first swellable seal, and wherein the first swellable material swells faster than the second swellable material in response to contact with an activating agent, wherein each of the second swellable seals contacts the first swellable seal other along a respective frusto-conical interface surface, and wherein the second swellable seals hold back ends of the first swellable seal from swelling while the first swellable seal pushes the second swellable seals outward into contact with a well surface in response to contact between the first swellable seal and the activating agent.
2. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to elevated temperature.
3. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to chemical attack.
4. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to contact with acid.
5. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to contact with oil.
6. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to contact with water.
7. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to contact with gas.
8. The packer of claim 1 , wherein the first and second swellable materials have different resistances to degradation due to contact with a well fluid.
9. The packer of claim 1 , wherein the first and second swellable materials swell at different rates.
10. The packer of claim 1 , wherein the first and second swellable materials have different extrusion resistances.