摘要 |
A swellable apparatus for filling a space in oil or gas apparatus and method of forming an apparatus is described. The apparatus comprises a hydrocarbon swellable body formed from an elastomeric material selected to expand on exposure to a hydrocarbon fluid such as EPDM. The swellable body has a first surface which is exposed to a hydrocarbon fluid, a first (inner) portion, and a second portion disposed between the first portion and the surface. The first portion comprises a fluid permeability structure which differs from the fluid permeability structure of the second portion. In one embodiment, the cross-linking density of an outer portion of the body is greater than the cross-linking density of an inner portion of the body.
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