Patent ID: 7527099

Claim:
A system for sealing a space in a wellbore formed in an earth formation, comprising a swellable body to be arranged in the wellbore in a manner so as to seal said space upon swelling of the swellable body, the swellable body when arranged in the wellbore being susceptible of being in contact with formation water flowing into the wellbore, the swellable body comprising a polymer matrix material provided with a compound soluble in said formation water, wherein the matrix material substantially restricts migration of the compound out of the swellable body and allows migration of said formation water into the swellable body by osmosis so as to induce swelling of the swellable body upon migration of said formation water into the swellable body, wherein the polymer matrix material comprises a vulcanized mixture of said compound and a mass of polymer material; wherein said compound comprises a salt.