Methods for passing a swelling agent into a reservoir to block undesirable flow paths during oil production

A method for recovering oil from a reservoir is provided. This method comprises passing a swelling agent into a permeable zone of the reservoir that allows fluid to flow between an injection well and a producing well. An aqueous solution is passed into the reservoir to contact the swelling agent, thereby causing the swelling agent to swell and substantially block the permeable zone. One or more injectants are passed into the reservoir to remove oil therefrom. The swelling agent inhibits the injectants from passing through the permeable zone, ensuring that the injectants pass through the areas of the reservoir containing oil.