Rule of Capture
The legal doctrine that you own the oil and gas your well produces, even if some of it migrated from beneath a neighbor's tract.
The rule of capture is the foundational doctrine of American oil and gas law: an operator owns the oil and gas physically produced from a wellbore on land it controls, even if some of that hydrocarbon migrated through the reservoir from beneath an adjoining tract. Because oil and gas are fugacious — they flow toward the lowest-pressure point, which is a producing well — the owner who drills and produces captures the production and owes the neighbor nothing for the drainage.
Historically this encouraged a destructive race to drill: each owner sank wells along the property line to capture as much of the common pool as possible before a neighbor did. That waste is exactly why states layered regulation on top of the rule — well spacing rules, density limits, and pooling all exist to curb wide-open capture.
For a mineral owner, the practical takeaway is that you generally cannot sue a neighbor for draining your minerals through a lawfully spaced well — the rule of capture bars that drainage claim. Your real protection is the right to drill (or lease) your own tract, plus the regulatory enforcement of correlative rights, which limits how the common pool is developed.