Petroleum Substances Used For Operations. Petroleum Substances that the Grantor may reasonably consider to be necessary for the Grantor's operations on the Lands for the production, treating, processing and storing of Petroleum Substances shall be exempt from the payment of the Overriding Royalty. Any Overriding Royalty exemption as aforesaid shall be restricted to that portion of production used as fuel for heaters, treaters, compressors, separators, instruments and similar equipment required to produce Petroleum Substances. The Petroleum Substances so used may be deducted from gross monthly production by the Grantor in quantifying the Overriding Royalty payable to the Owner under the preceding subclause. The Grantor shall not be granted any Overriding Royalty exemption from the production of Petroleum Substances used for reservoir injection or pressure maintenance, secondary and heavy oil recovery or upgrading schemes, or fuel and/or feedstock for any gas plant, refinery, satellite or multi-well battery.
