US Patent 7950468 Wellbore plug

A method of retrieving at least a first plug and a second plug of the same type from a wellbore, wherein when the plugs are set in the wellbore each plug has a valve in a closed position blocking flow of fluid through the plug and a sealing mechanism expanded into engagement with a wellbore casing providing a seal between the plug and the casing, includes the steps of connecting a conveyance to the first plug; releasing the first plug; moving the first plug into connection with the second plug; and retrieving the first and the second plug from the wellbore simultaneously.