If any section of said pipe line shall not be completed within one year after the approval by the Secretary of the Interior of said section, or if any section of said pipe line shall be abandoned or shall not be used for a period of two years, the right of way granted in sections 966 to 970 of this title as to any uncompleted, abandoned, or unused section of said pipe line shall be forfeited to the extent that the same is not completed or is abandoned or unused at the date of the forfeiture, without further action or declaration on the part of the Government or any proceedings or judgment of any court.