Pugh Clause
A lease clause that releases acreage or depths not held by production, so one producing well can't tie up the whole tract.
A Pugh clause limits how much of a lease an operator can hold once the primary term ends. Without it, a single producing well can keep the entire leased tract — and every depth under it — held by production. A Pugh clause carves off the parts that are not being produced or developed and returns them to the mineral owner.
A horizontal Pugh clause releases acreage outside any producing pooled unit. A vertical Pugh clause — closely related to a depth severance — releases the deeper or shallower zones the operator never developed. Both free up your minerals for a new lease and a new bonus.
Pugh clauses are negotiated, not automatic. They are one of the most valuable protections a mineral owner can ask for.