A more thorough explanation:

The nonapportionment rule is a legal doctrine that applies to oil and gas leases. It states that if a piece of land is leased for mineral extraction and is later subdivided during the lease term, the royalties accrued from the lease belong exclusively to the owner of the land where the producing well is located.

For example, let's say Grey granted a lease to Wainwright for mineral extraction on a piece of land. Later, Grey sold half of the land to Svenson. If the well on Wainwright's half begins producing minerals, only Wainwright would be entitled to the royalty. Svenson would not receive any portion of the royalty, even though the land was originally leased by Grey.

The nonapportionment rule is different from the apportionment rule, which states that royalties should be divided among the owners of the subdivided land based on the percentage of land they own. However, the nonapportionment rule is the majority doctrine in the United States.