[[Recovery]] methods which increase ultimate oil production beyond that achievable with primary and secondary methods. These methods are usually employed in the latter stages of conventional secondary flooding applications, but may be implemented early in the secondary application or in combination with the secondary method. These oil recovery methods enhance the production of oil by increasing the proportion of the [[reservoir]] affected, reducing the amount of [[residual oil]] in the swept zones and reducing the [[viscosity]] of thick oils.

The tertiary methods usually are divided into three broad groups: thermal, miscible and chemical. See also [[primary recovery|primary]] and [[secondary recovery|secondary]] recovery.