TEMPERATURE DEPENDENT SWELLING OF A SWELLABLE MATERIAL

A swellable packer can include a material which swells when contacted with a swelling fluid, and a barrier comprising a highly crystalline polymer which is substantially impermeable to the swelling fluid. A method of controlling swelling of a material can include positioning the material and a barrier in a well, the barrier preventing contact between the material and a swelling fluid, the barrier comprising a polymer, and increasing a permeability of the barrier to the swelling fluid in response to the barrier polymer being heated to its crystallization temperature. A well system can include a material which swells in response to contact with a hydrocarbon gas, and a barrier which comprises a crystalline polymer, the polymer being substantially impermeable to the hydrocarbon gas, whereby the polymer initially prevents swelling of the material, but the polymer becomes increasingly permeable to the hydrocarbon gas when heated to its crystallization temperature.