An Overriding Royalty Interest (ORRI) is an oil and gas interest is separated from the participatory interest of what is called the working interest. It is percentage of gross production that is not charged with any expenses of from an oil and/or gas well. An ORRI is a covenant running with the land between the assignor and assignee. However, it expires if the associated leases expire.
The overriding royalty interest, for well units, is calculated as follows:
Where the terms are defined as follows: