A well tool including swellable material and integrated fluid for initiating swelling. A well tool includes a swellable material and a reservoir for containing a fluid of a type which causes the swellable material to swell. A method of swelling a swellable material included in a well tool includes the steps of: positioning the well tool in a well; and then activating a fluid to cause swelling of the swellable material. A method of swelling a swellable material includes the steps of: providing the swellable material which is capable of swelling when contacted by a fluid; positioning the swellable material in an environment in which the swellable material is contacted by another fluid which does not cause the material to swell; and swelling the swellable material by contacting the swellable material with the first fluid while the swellable material remains in contact with the other fluid.